Comment 1 for bug 673823

I had the same problem -- Ubuntu 10.10 amd64. While it is not in the online documentation, the man page for origami documents the switch -p amd64 which installs the 64 bit version of folding at home successfully.

To recover from a 32 bit installation (substituting your user name for 'username' and your team for '45104'

sudo origami stop
sudo origami erase
sudo origami install -p amd64 -u username -t 45104