Import of OpenPGP Public Keys not working

Hello
I just tried to import some OpenPGP Public Keys and it stopped after the selection of the keys. (File selection -> Selection of key -> Then it says importing and nothing happens)

I am using the following setup:

XenServer 5.5 VM (see signature)
Firefox 13 enUS (current update state)

The PGP file was exported using Thunderbird 13 w/ enigmail in the current version on Mac OS X Lion (updated to latest)

greetz
chas0rde