Internal Server Error, Unable To Upload/Attach Any Files

Greetings!

do we currently have a problem in attaching files? recently, I am unable to attach any files to this forum which made me hard to explain my posts. I tried using Firefox, IE and Chrome to upload files but still encountering Error 500(IOError ... etc), I tried to uncheck the advance attachment, and I got this error when uploading files.

"Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, webmaster@excelforum.com 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 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request."