If you specify a WEBFORMS value with an inadvertent trailing space, when you try to apply the form when editing a page you get redirected to the oopsnoform termplate.
This may be related to TWikiFormsAndCommaDelimitedLists : it sounds as though the same or similar unforgiving code is being used to split the lists.
Test case
Set WEBFORMS to the name of a valid form followed by a space
Edit a page of the web and press the Add Form button
Fixed and in TWikiAlphaRelease.
-- PeterThoeny - 16 Feb 2002
Might be a good idea to strip trailing spaces from all variable Set lines.
-- RichardDonkin - 17 Feb 2002