I downloaded and installed this. I then copied IronPortable.ini to the installation directory and edited the copy so that I had:
I can save the passwords OK on one machine, and view them without problem. When I move the stick to another machine and fire-up Iron, the passwords list shows the URLs but the passwords themselves are blank.
I'm switching between an Windows XP and a Windows 7 machine in case that's relevant.
I also use Google Chrome (currently 10.0.648.204 but I've been using it for some time through several versions) on the same stick, on the same machines. Portable passwords works fine on that so there doesn't appear to be any underlying issue to do with the stick or machines.