Ok, I see part of the problem,
The file /home/cuddles/.kde/share/apps/kfmexec/tmp/18189.0.viewtopic.php cannot be found. Please check the location and try again.
I checked to see if I had a similar location on my system, and I only have /.kde/share/apps/kfm/ instead of kfmexec. Perhaps you need to create that folder as well as tmp first? That's probably why it dies with konqueror or mozilla when calling a hyperlink from within kmail.

FWIW, I use mozilla's email client and browser, so when I click on a link in mozilla's email, it opens in mozilla's browser. You could copy the link from kmail as a workaround, but that's a real drag, IMO.