Hi all. I want to check for not null value constraint for all tables in database . I tried the following but when i run it i get the following error:

Compile error:
Invalid Next control variable reference

I be happy if some one one help me fix this error.if i remove the bold lines the program workes well but it does not put not null for table fileds that requries value.

picture of the output without the bold part

http://i5.photobucket.com/albums/y18...07/notnull.jpg


Code:
Option Compare Database

''This module displays field name and type in a massage box
Function ShowFields(pTable As String) As String

Dim db As Database
Dim rs As Recordset
Dim I As Integer
''Dim j As Integer
Dim n As Integer
''Dim NL As String
Dim strHold As String, ST As String
''Dim x As Variant

''NL = Chr(13) & Chr(10) ' Define newline.

Set db = CurrentDb

Set rs = db.OpenRecordset(pTable)

n = rs.Fields.Count
ReDim x(n - 1, 1) As String

'''ST = "Create Table " & pTable & vbCrLf
''adding Create table and table name to statement
ST = "Create Table " & pTable & vbCrLf & "("

For I = 0 To (n - 1)

For Each fld In tbl.Fields 

ST = ST & rs.Fields(I).Name & " " & FieldType(rs.Fields(I).Type) & "," & vbCrLf

               
               If fld.Required = True Then
                  ST = ST & " NOT NULL" & " "
               Else
                  ST = ST
               End If


Next I
rs.Close
db.Close
Set db = Nothing

ShowFields = ST '' returns the fields name to main function
End Function
on click even code

Code:
    For Each T In db.TableDefs
    '''Skip the system tables
        If Left(T.Name, 4) <> "MSys" Then
       
           
           ''' this line determines the primary key of the table
           ''' by calling GetPk function from module
           
                pk = Left(GetPK(T, db), InStr(1, GetPK(T, db), "<-") - 1)
                
                
cont = cont & ShowFields(T.Name) & vbCrLf & " primary key " & "(" & pk & ")" & vbCrLf & ")" & vbCrLf
              

          
        End If
    Next T
    
    ''' This line of code post the generated table statment to a massage box
    
    MsgBox cont