email pipe -> attachment problem (zip files)

Hi, I just wrote an script, which scans emails passed to it via a pipe and adds the content to a MySQL database. Attachments are also supported, however, zip files simply don't work. They get processed & saved into the database just fine, but once i grab such a zip file from the database, it shows up as being empty, whereas it still has the same filesize as the file attached to the email. I checked and the zip file attachment gets base64 encoded, which the script supports as well, so i am quite clueless, what could be causing the zip file to appear empty. I only found some similar posts in the net, but none offered a solution. If anyone knows, what could be the possible problem with those zip files, then please let me know :) Thanks, Duncan