I'm using F-Spot Version 0.4.3.1 on Ubuntu 8.04 / Hardy Heron
For a long old time it didn't occur to me that the problem with my uploads might be that I needed to enable a Gallery plugin (I did find the answer in the cough F-spot help.) so if you're searching around trying to figure out why you're getting errors like "the following error was encountered while attempting to login: unhandled exception" or f-spot is just timing out when you try to add your Gallery2 to the "export to web gallery" function, you might consider reading the help files or just go into your gallery installation and look under "plugins" for the "remote" plugin.
Since I searched a zillion forums before I thought of reading the help files, I thought I ought to share this one.