"The URI you submitted has disallowed characters" question..

[eluser]aroman[/eluser]
Yes , i also got an error . I tried to put a % in the url . Error says " Bad request!
Your browser (or proxy) sent a request that this server could not understand.
If you think this is a server error, please contact the webmaster.
Error 400
localhost
09/16/07 11:13:26
Apache/2.2.0 (Win32) PHP/5.1.2 "

Whats wrong with my localhost ?