Only index page is displayed - all links give "page not found" error

[evankirby]

Our Coppermine install is at http://www.genkijacs.com/gallery/.
Until recently it was working fine. When I try it today, the main page (linked above) displays perfectly.
However, clicking on any of the albums, categories or images on that page brings a "file not found" error. So, no images or albums can be displayed, although the thumbnails and information on the main index page are displayed correctly.
All of the image files themselves are still where they used to be.

After this problem occurred, I upgraded to the latest version (1.4.14) to see if that would solve the problem, but the same thing occurs.
I also tried updating all thumbnails and files using Admin tools, and even resetting the counters, but nothing changed.
I have a feeling there might be a really simple solution to this - if so, please tell me! As far as I know, no settings either on the server or with Coppermine itself were changed in the interim, between when it worked and when it didn't work. But obviously something must have changed...
If more information is needed, I'll try to post what I can. No error message is displayed, just the standard "page not found" page, so I don't have a debug dump to paste here, unfortunately.

Thanks in advance for any help you can provide!

[François Keller]

desable sef plugin. d'ont use it if it cause problem on your gallery

[evankirby]

Perfect! That fixed the problem. Thank you very much for your help!