And indeed the problem was with the fact that I was subclassing the DTML Document, which as explained in http://www.zope.org/Members/AlexR/ZClassIDBug somewhat mangles the Id property. Public thanks to Rik Hoekstra <rik.hoekstra@inghist.nl> for suggesting that. I added this fix (from the page I mention above) to the constructor method,

<!--#with "myZClass.createInObjectManager(REQUEST['id'], REQUEST)"--> <dtml-call "setName(REQUEST['id'])"> <!--#/with-->

And when I try creating a new object, it blows up in my face with this error:

Walter - this is sort of a tricky one :( The problem is that the ZClass id bug is a legitimate bug (fixed in the 2.2 series), but your fix uses a method that should never have been accessible in the first place (and in fact the hotfix makes it inaccessible, as it should have been all along). So there are two things you could do here to get along until you can upgrade to 2.2. One, you could edit the __init__.py in the Hotfix product's directory and comment out the line: DocumentTemplate.DT_String.String.setName__roles__=[] ...and restart Zope. That will make the setName method unprotected again though, so don't do this lightly. By unprotected I mean that other people could call setName on _your_ objects and screw things up if they wanted to. An alternative would be to create an external method like the following in your class: def temporary_hack(self, id): self._setId(id) ...and try using: <!--#with "myZClass.createInObjectManager(REQUEST['id'], REQUEST)"--> <dtml-call "temporary_hack(REQUEST['id'])"> <!--#/with--> That should let you solve it without reopening a security hole. Hope this helps! Brian Lloyd brian@digicool.com Software Engineer 540.371.6909 Digital Creations http://www.digicool.com