Thanks to Jeff Ragsdale, we've finally been able to kill a longstanding bug that allows POST requests to interfere with each other. Symptoms include corrupted or aborted File and Image uploads, and stupid-log messages about "AttributeError: data" killing threads.
There are two different HTTPServer.py replacements avaliable. One is valid for all Zope 2.0.x and 2.1.x versions, the other for 2.2.0 through 2.2.4. As of version 2.2.5, Zope incorporates this fix.
PLEASE BACK UP /ZServer/HTTPServer.py, then replace it with the downloaded file.