my site stopped working

Hello,
our site behaves strangely these days. At first i could not upload any photo via media uploader. Then site became down. Only site works if i deactivate wp-hide from the back end via ftp. If i change plugin name site works. But i can not login to admin area. Because login url does not work either. Also, some photos does work at the moment. What do you think it could be.

Thanks

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