问ASP.NET，Server 2008 R2，System.OverflowException

EN

Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load
    If PreviousPage IsNot Nothing AndAlso PreviousPage.IsCrossPagePostBack Then
        Dim params(5) As SqlParameter
        params(0) = New SqlParameter("@Name", PreviousPage.Name.Text)
        params(1) = New SqlParameter("@Qualification", PreviousPage.Qualification.Text)
        params(2) = New SqlParameter("@ContactNo", PreviousPage.ContactNo.Text)
        params(3) = New SqlParameter("@Expertise", PreviousPage.Expertise.Text)
        params(4) = New SqlParameter("@Comments", PreviousPage.Comments.Text)
        params(5) = New SqlParameter("@Affiliation", PreviousPage.Affiliation.Text)
        DAL.DoInsertSP(params)
    End If
End Sub

Public Shared Function DoInsertSP(ByRef params As Array) As Byte
    Dim result As Byte = 0
    CreateConnection()
    cmd = New SqlCommand("sp_InsertExpert", conn)
    cmd.CommandType = CommandType.StoredProcedure
    cmd.Parameters.AddRange(params)
    Try
        result = CByte(cmd.ExecuteNonQuery())
    Catch ex As Exception
        conn.Dispose()
    End Try
    Return result
End Function

USE [dbherpes]  

 @Name             nvarchar(30) = null,

 @Qualification  nvarchar(40) = null,

 @ContactNo      nvarchar(13) = null,

 @Expertise      nvarchar(30) = null,

 @Comments       nvarchar(100) = null,

 @Affiliation    nvarchar(50) = null AS

 SET NOCOUNT ON;

 INSERT INTO Expert (Name, Qualification, ContactNo, Expertise, Comments, Affiliation) VALUES (@Name, @Qualification, @ContactNo, @Expertise, @Comments, @Affiliation)