Change request validation error message?

From: Bill (
Date: 09/18/03

Date: Thu, 18 Sep 2003 09:48:14 -0700

The request validation feature in verision 1.1 throws an
error message when non-encoded html characters are present
in input text. This is a nice feature. But is it possible
to provide a more user-friendly message than the one sent
to the offending user?