Fix Joomla Error

I need to get a Joomla web site fixed. I am having problems in uploading files in media manager. I get the following error --------------------------------------------------------------------- Internal Server Error The server encountered an internal error or misconfiguration and was unable to complete your request. Please contact the server administrator and inform them of the time the error occurred, and anything you might have done that may have caused the error. More information about this error may be available in the server error log. Apache Server at [login to view URL] Port 80 --------------------------------------------------------------------- I am having problems in installing the modules as well. I get the same message when i install the module. There are few other technical problems in the site which need to be fixed, which we will fix as we proceed.