relative paths and get variables

Hi

I am currently developing a site and I came across a weird behaviour
which I just cannot understand:

The whole thing was working and I could include files from other
directories using relative paths with or without passing variables and
whatever the method.

I implemented a cookie. It would not work unless I used ob_start( ); (I
am still not sure why - anyway)

Now the cookie works but I get the following puzzling error:
Say I am checking something and if it's wrong, I want to display an
error message. I use a nice error file:
include("../error.php");
This works except I want to tell it which error to print so I use
include("../error/error.php?error=access");
for example. And this does not work anymore but produces the error:
Warning: main(): Failed opening '../errors/error.php?error=access' for
inclusion (include_path='.:/usr/lib/php') in ...blah.

I could get around it having a separate file for each error but that's
not the point, now is it?.... :) And I need to pass variables to other
files too anyway!

I have checked my php.ini settings and the pwd is included so I should
have no problems with relative paths.

It looks like the argument to the php file (?error=access) is
interpreted as part of the filename but why would that not happen before
I used a cookie? What would a set_cookie and ob_start have to do with
apache/zend's interpretation of a filenames?

Any help would be greatly appreciated as I'd rather understand what's
going on than just dropping the problem... :)


Thanks a lot!


C