An appropriate representation of the requested resource /page.php could not be found on this server

Question

In a page in my website I have a link as below:

<a href="page.php?ref=selectquiz">Go to the page.php</a>

When I click the link, I get the following error:

406 Not Acceptable
An appropriate representation of the requested resource /page.php could not be found on this server.

This is the header information which I captured via Live HTTP headers:

EDIT:
That's really weird, because when I convert the parameter value from selectquiz to:
selectq selectqu ... selectquiz

it's not working, but when when I type selec it is OK!! (In all browsers)

Answer 1

I'm getting the same error message, but it seems to be a generic problem with mine when i try to add images to posts/pages etc, i can upload images but they just won't. I've tried re-uploading the images, installed a fresh wordpress download, tried different themes, no change.