Server Mismatch

I like to use custom content in my games…to be honest i’m addicted to it but i’m having a problem. I head hacked one of the german models but i get a Server Mismatch message but when i use someone elses content i don’t. Anyway i can fix this?
Here’s the hack i’m using

http://filesmelt.com/downloader/I_DID_IT.jpg

I’ve never even heard of the Server Mismatch error, tried playing on different server or with different custom content?

Sorry i misread it it’s a file consistancy error but i dont get it with other people content :confused: