The bug was supposed to be fixed as part of SP1, and indeed it appeared to be fixed for a while. But I, and several others have since encountered it numerous times.
Microsoft knows that this bug is still present, but at this point they have been unable to track down repro steps, as have I.
If you or anyone else reading, who have experienced this bug, can get exact steps to repro this bug which causes the domEventHandler block in the manifest.xsf file to be removed (i.e. erase your rule bindings), please, please post them here so we can get them to Microsoft to be able to fix this bug for good.
For now, I have outlined ways to avoid this bug in my blog entry dated 29 June 2004:
http://www.infopathdev.com/blog/PermaLink.aspx?guid=3d25d93a-887b-40f2-bba6-d77ed3c808d2
Greg Collins [InfoPath MVP]