The URI you submitted has disallowed characters.

[eluser]Unknown[/eluser]
Does anyone have any idea on how to fix this error message?

I have am running apache 2.2.11 with windowsXP. the url looks like:
http://www.localhost.com/site1/index.php/test

[eluser]Chad Fulton[/eluser]
I suspect this is the result of a known bug in CodeIgniter. Essentially, there is a problem in the way CodeIgniter checks URIs for disallowed characters. PHP 5.2.9 and PHP 5.3 fixed an error in the implementation of a function and, in doing so, broke out-of-the-box CodeIgniter installations on systems running them.

You can take a look at the bug report here: http://codeigniter.com/bug_tracker/bug/7126/
There are details in the bug report on the way to fix this problem in PHP versions effected.

Jesse Collis reported this bug for PHP 5.2.9 and I reported it for 5.3, back in March!.

I have to say I am dissapointed in the CodeIgniter development team, given that not only have they not fixed this critical error, they haven't even responded to the bug report.

[eluser]Unknown[/eluser]
Chad,
Thank you very much. Just as my development team thought this was an interesting behaviour, we were also able to conclude it had everything to do php 5.3

We were able to get things going however by setting $config['enable_query_strings'] = TRUE.

This allowed default index.php/controller/method as well as index.php?c=method&m=method to work just fine.