Hi! Well, two blasts from the past - Ricky and Dragonfly, all in one post ... :) Nice to see you both.
I think Dragonfly is currently being resuscitated from a deep sleep in the lands of Abandonment. Don't know whether the original authors are still interested in it, but I gather that Kanen is going to absorb the frameworks and get them updated.
But to the point: I reproduced this error easily enough, and fixed it easily enough by changing line 174 of ./dragonfly-newlisp/example-site/dragonfly-framework/lib/request.lsp to
instead of
I think that the empty string evaluates to true, so (when {} 1) evaluates the 1.
This may not be the cause of the problem, of course, merely the symptom. So plenty of scope for research!