[Zope] ZServer ftp problem, when not running as root

Hello zopies, It seems that if zope/zserver is not running as root, the ftp functionality is not working. This means, that uploaded files all have length 0 or 144 bytes, depending on the version of zope. This also appears in the current (4/28) public cvs code. Is there a permission problem and has anyone discovered a similiar drawback? TIA Christian