The simpler media website CMS
There does not exist a ".htaccess" file in the root; there is a similar file in the /zp-core directory (named htaccess w/o the leading "."). I've copied it to the root and renamed it; no dice. I've changed the permissions of the files and folders to 755 and 777. did not work. I've installed versions 1.2.9, 1.3.1.1, 1.3.1.2, and the latest trunk from 2010-12-12; none have worked.
The server encountered an internal error or misconfiguration and was unable to complete your request.
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More information about this error may be available in the server error log.
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Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Comments
In addition to that, maybe you should find out what your server logs are telling you and report that back as well (as you no doubt have seen int the error messages you have posted.)