Problems with Validation Summary and Required Field Validator under Windows 2003

[Alfonso Alvarez]

Hi:
I have a webpage that uses a Required field validator to validate a
textbox and a Validation Summary to show de information.
This works perfect under iis in windows XP but when I try it under iis
in Windows 2003 no validates and the code runs with wrong fields.
Any solution to this problem?
Thanks a lot
Alfonso Alvarez