Someone has shared a Picasa web album (Limited, anyone with the link), but I can't download it to Picasa. The following alert appears:

Firefox doesn't know how to open this address, because the protocol (picasa) isn't associated with any program.

I have Picasa 3.0.0 installed on Ubuntu 11.04, I remember it saying something about registering the picasa protocol with Firefox during the installation.

I have Firefox 6.0.2, and these settings are present in about:config

network.protocol-handler.app.picasa;/usr/bin/picasa
network.protocol-handler.expose.picasa;true
network.protocol-handler.external.picasa;true

Picasa is located here:

$ which picasa
/usr/bin/picasa

Is there something I can do to make this work?

PS: I hope this is not off-topic here, and I can't find the "picasa" tag. Could someone please add it, if appropriate?