Either a file was not uploaded to the server or it's not executable. You will need to either upload the file(s) again or check file permissions on the server.
First of all, please try to show a little patience and do not bump your threads every 5 minutes.
That being said, did you try the suggestion posted above by KK? Also check out the error in the console and post it here. What about the acp error log, anything logged in there?
Another thing, before the error started to happen, did you do any modification to your forum?