Return Error Message from SQL Server 2000

Dear all,

I have a program using ADO connect to SQL Server2000. Some problem occur.

The program contain many module. One module can show the normal SQL Error
return from Server such as "Foreign Key Error"

Another module cannot show any message, and no error message box pop out.
But, in SQLServer, there really a error message "Foreign Key Error".

The most strange is, in different computer, some can show the Error box in
that problem module and some had no error message box pop out...

can anyone help me?