Good Morning!
Simple cache functions: First in the bed, first out of the bed
a) Perhaps we missunderstand each other: Your Wiki-Login works (wiki form ist shown but vb-login executed) and so does mine.
It irritated me to see a wiki-login, but I think it's the best solution to leave this that way since the wiki-login will be executed only in exception cases.
b) I put back the userlogin.php without your special edit for
BRotondi's case... and get an error again: If I use the wiki-login I get the vB-confirm but then instead of the mainbage the followin error follows:
http://www.sinnimleben.net/index.php/Hauptseite not found
=> Same error we had with the forum:
/wiki is missing
Bruno