Need help with File Upload

hi there, i´m sorry to post that stupid message, but i really need help in finding the solution to a maybe small problem. I´m trying to do a simple file upload (jpeg) with the "copy" function. the destination directory is set to chmod 0777, the files are copied to this directory (with the correct extension .jpg), but if i try to open them, the files seem to be corrupt. (the filesize seems to be o.k.). i tried several upload-scripts to test the situation, but the result is everytime the same. on my test-server, i´m running Yellow Dog Linux (PPC) with PHP4.0.4pl1. I tried the uploads from different browsers. Can anybody pls help me find the bug ?? thanx!!!! best regards, walter