Error # 94 Invalid use of Null in Procedure: send_form send

[QNguyen]

Here is the SQL script

CREATE TABLE [dbo].[Messages] (
[User] [varchar] (40) NOT NULL ,
[Pin] [varchar] (40) NOT NULL ,
[Message] [varchar] (400) NOT NULL ,
[Carrier] [varchar] (40) NOT NULL ,
[Date_Time_Requested] [datetime] NOT NULL ,
[Date_Time_Sent] [datetime] NOT NULL ,
[From] [varchar] (80) NOT NULL ,
[Sent] [int] NOT NULL ,
[Error] [int] NOT NULL ,
[ASCII_File] [varchar] (80) NOT NULL ,
[Lock] [int] NOT NULL ,
[Scheduled] [int] NOT NULL ,
[Reliapage_Index] [int] NOT NULL ,
[Repeat_Interval] [int] NOT NULL ,
[Repeat_Stop] [datetime] NOT NULL ,
[Station] [int] NOT NULL ,
[Message_ID] [int] IDENTITY (1, 1) NOT NULL ,
[Retries] [int] NOT NULL ,
[Last_Try] [datetime] NOT NULL ,
[Transaction] [int] NOT NULL ,
[Property_No] [varchar] (15) NOT NULL
) ON [PRIMARY]