Do that twice, running two firefoxes using two profiles, then click a link in a third application. This tends to try to launch a third firefox process which hangs for a while then says "application already running".

Okay, so you run one of them without no-remote. I had some issues with that, but it mostly works. Now how do you change the default profile? You completely stop firefox, update your shortcuts and finally, in my case, give up on using multiple profiles with firefox on a day to day basis.