Registration form problem. String or binary data would be truncated

I have created a registration form. It works fine IF ALL fields are filled. However, all fields are not required. When I test the registration page and leave a field blank, I receive the following message:

Exception Details: System.Data.SqlClient.SqlException: String or binary data would be truncated. The statement has been terminated.

Stack Trace:

[SqlException: String or binary data would be truncated.
The statement has been terminated.]

Even if I leave a validated field blank, I receive the same message instead of the required field validation control error message.

Here is the code for the registration page. I use web matrix to create the code as directed in the tutorial.

Can anyone help a newbie?

Function AddMember( _
 ByVal firstName As String, _
 ByVal lastName As String, _
 ByVal streetAddress1 As String, _
 ByVal streetAddress2 As String, _
 ByVal memCity As String, _
 ByVal state As String, _
 ByVal zipCode As String, _
 ByVal primAreaCode As String, _
 ByVal primPhone As String, _
 ByVal primExt As String, _
 ByVal secAreaCode As String, _
 ByVal secPhone As String, _
 ByVal secExt As String, _
 ByVal memEmail As String, _
 ByVal memUserID As String, _
 ByVal memPassword As String, _
 ByVal secretQuestion As String, _
 ByVal secretAnswer As String, _
 ByVal memBirthMonth As String, _
 ByVal memBirthDay As String, _
 ByVal memBirthYear As String) As Integer
 Dim connectionString As String = "server='(local)'; trusted_connection=true; database='Members'"
 Dim dbConnection As System.Data.IDbConnection = New System.Data.SqlClient.SqlConnection(connectionString)
 Dim queryString As String = "INSERT INTO [Members] ([FirstName], [LastName], [StreetAddress1], [StreetAddress2"& _
"], [MemCity], [State], [ZipCode], [PrimAreaCode], [PrimPhone], [PrimExt], [SecAr"& _
"eaCode], [SecPhone], [SecExt], [MemEmail], [MemUserID], [MemPassword], [SecretQu"& _
"estion], [SecretAnswer], [MemBirthMonth], [MemBirthDay], [MemBirthYear]) VALUES "& _
"(@.FirstName, @.LastName, @.StreetAddress1, @.StreetAddress2, @.MemCity, @.State, @.Zip"& _
"Code, @.PrimAreaCode, @.PrimPhone, @.PrimExt, @.SecAreaCode, @.SecPhone, @.SecExt, @.Me"& _
"mEmail, @.MemUserID, @.MemPassword, @.SecretQuestion, @.SecretAnswer, @.MemBirthMonth"& _
", @.MemBirthDay, @.MemBirthYear)"
 Dim dbCommand As System.Data.IDbCommand = New System.Data.SqlClient.SqlCommand
 dbCommand.CommandText = queryString
 dbCommand.Connection = dbConnection
 Dim dbParam_firstName As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_firstName.ParameterName = "@.FirstName"
 dbParam_firstName.Value = firstName
 dbParam_firstName.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_firstName)
 Dim dbParam_lastName As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_lastName.ParameterName = "@.LastName"
 dbParam_lastName.Value = lastName
 dbParam_lastName.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_lastName)
 Dim dbParam_streetAddress1 As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_streetAddress1.ParameterName = "@.StreetAddress1"
 dbParam_streetAddress1.Value = streetAddress1
 dbParam_streetAddress1.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_streetAddress1)
 Dim dbParam_streetAddress2 As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_streetAddress2.ParameterName = "@.StreetAddress2"
 dbParam_streetAddress2.Value = streetAddress2
 dbParam_streetAddress2.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_streetAddress2)
 Dim dbParam_memCity As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_memCity.ParameterName = "@.MemCity"
 dbParam_memCity.Value = memCity
 dbParam_memCity.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_memCity)
 Dim dbParam_state As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_state.ParameterName = "@.State"
 dbParam_state.Value = state
 dbParam_state.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_state)
 Dim dbParam_zipCode As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_zipCode.ParameterName = "@.ZipCode"
 dbParam_zipCode.Value = zipCode
 dbParam_zipCode.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_zipCode)
 Dim dbParam_primAreaCode As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_primAreaCode.ParameterName = "@.PrimAreaCode"
 dbParam_primAreaCode.Value = primAreaCode
 dbParam_primAreaCode.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_primAreaCode)
 Dim dbParam_primPhone As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_primPhone.ParameterName = "@.PrimPhone"
 dbParam_primPhone.Value = primPhone
 dbParam_primPhone.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_primPhone)
 Dim dbParam_primExt As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_primExt.ParameterName = "@.PrimExt"
 dbParam_primExt.Value = primExt
 dbParam_primExt.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_primExt)
 Dim dbParam_secAreaCode As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_secAreaCode.ParameterName = "@.SecAreaCode"
 dbParam_secAreaCode.Value = secAreaCode
 dbParam_secAreaCode.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_secAreaCode)
 Dim dbParam_secPhone As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_secPhone.ParameterName = "@.SecPhone"
 dbParam_secPhone.Value = secPhone
 dbParam_secPhone.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_secPhone)
 Dim dbParam_secExt As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_secExt.ParameterName = "@.SecExt"
 dbParam_secExt.Value = secExt
 dbParam_secExt.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_secExt)
 Dim dbParam_memEmail As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_memEmail.ParameterName = "@.MemEmail"
 dbParam_memEmail.Value = memEmail
 dbParam_memEmail.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_memEmail)
 Dim dbParam_memUserID As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_memUserID.ParameterName = "@.MemUserID"
 dbParam_memUserID.Value = memUserID
 dbParam_memUserID.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_memUserID)
 Dim dbParam_memPassword As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_memPassword.ParameterName = "@.MemPassword"
 dbParam_memPassword.Value = memPassword
 dbParam_memPassword.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_memPassword)
 Dim dbParam_secretQuestion As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_secretQuestion.ParameterName = "@.SecretQuestion"
 dbParam_secretQuestion.Value = secretQuestion
 dbParam_secretQuestion.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_secretQuestion)
 Dim dbParam_secretAnswer As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_secretAnswer.ParameterName = "@.SecretAnswer"
 dbParam_secretAnswer.Value = secretAnswer
 dbParam_secretAnswer.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_secretAnswer)
 Dim dbParam_memBirthMonth As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_memBirthMonth.ParameterName = "@.MemBirthMonth"
 dbParam_memBirthMonth.Value = memBirthMonth
 dbParam_memBirthMonth.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_memBirthMonth)
 Dim dbParam_memBirthDay As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_memBirthDay.ParameterName = "@.MemBirthDay"
 dbParam_memBirthDay.Value = memBirthDay
 dbParam_memBirthDay.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_memBirthDay)
 Dim dbParam_memBirthYear As System.Data.IDataParameter = New System.Data.SqlClient.SqlParameter
 dbParam_memBirthYear.ParameterName = "@.MemBirthYear"
 dbParam_memBirthYear.Value = memBirthYear
 dbParam_memBirthYear.DbType = System.Data.DbType.String
 dbCommand.Parameters.Add(dbParam_memBirthYear)
 Dim rowsAffected As Integer = 0
 dbConnection.Open
 Try
 rowsAffected = dbCommand.ExecuteNonQuery
 Finally
 dbConnection.Close
 End Try
 Return rowsAffected
 End Function

Do u have all the fields in the table defined as "not null"?|||no. some fields allow nulls.