[RE-PHRASE] PHP ZIP Class

I am in need of a PHP class or script or something that will allow me to designate a group of files to be zipped up, including PDF files, automagically. It must be compatible with WinZip as that is what the user will have access to. I have tried several things, a couple of classes, and some other tricks to no avail. There seems to be an issue with PDF's that I cannot figure out. The files are usually 1 byte too short when you try to open them after unzipping them, and are therefore corrupt. If anyone is aware of something would you please let me know? I am even willing at this point to add a couple of layers of abstraction to make this work as long as the process is relatively invisible to the end user. My desire is that it works like this; User clicks link [start automagic stuff] *whirring* //determine which files should go into archive *clicking* //put files in archive [/end automagic stuff] User presented with dialog box to save archive Any and all clues are appreciated.