Keit and Lazymimi I did not think of this before, but if you are using the official clients, they may use a anti-hack system like gameguard or hackshield, if that is the case when you change the bin files the system will detect that the bin files have been changed from their original bin files and that will cause the client to close and tell you that the files have been changed.
If you two will take a screenshot of the exact error or errors and upload it to this thread it will give me (or anyone else) a better understanding of the issue.
in the meantime I will look into getting a classic server running and see what I can figure out. I can also attempt to compile the classic source code and see if I can get a working set of files for you guys to use.
(Edit) ok that was weird, I am guessing a mod may of done it or some type of plugin on the forums is responsible but my original reply to Lazymimi got combined with my reply to Keit and moved to post #3