500 error and 404 error, only on pro!

[colonelstem]

hello,

i had xupload free running perfectly (minus the taskbar), so i purchased the pro version and now after after i hit "upload files" the upload begins, the task bar and all the upload info flash onscreen for about a second then I get this error:

"The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, (blanked out for security) 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.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request."

i get the same message if i just try to run the post.php file as well.

After all this the files never make it to my uploads folder (which worked fine when i had the xupload free version running)

I have quadruple checked the permissions and url paths, and used the "http://sibsoft.net/cgi-bin/Tools/nl.cgi " tool to remove the windows line breaks on my .cgi files (im on a linux server). I did everything I read in the forums to no avail.

Do i have to remove the windows line breaks from anything else besides the .cgi files, like possibly the .pm files?

please help!

[colonelstem]

also I tried the adding the suggested commands to the .htaccess with no success.

ive tried on mac snow leopard (safari and firefox) as well on a pc vista (explorer and firefox).