Thread:Project:Support desk/MediaWiki 1.20.0: Error creating thumbnail: Shared object "libpcre.so.1" not found, required by "liblqr-1.so.3"/reply

That is no MediaWiki error. MediaWiki is written in PHP, so if a command by MediaWiki failed, you would most likely get a PHP error; but this is no PHP error. It looks like an error message from the server. Possibly a missing dependency for ImageMagick, so that ImageMagick does not work correctly. Ask your host to fix their broken setup.