Is it a server error or a script error? Do you know? I spent a good amount of time writing my own error traps and it is possible.
If Request("FormField") = "" Then
MyError = "Form value empty"
End If
If it is processing through an auto subit then try something like
If Request("FormField") = "" Then
Response.Write("<input type=hidden name=myerror value=""form value empty"">")
End if
I have a couple other ideas but the server I use for a playground appears to be offline t the moment. In other words, I have more urgent needs at the moment.
Hope that helps. (Off the top of my flat head)