When we switched to Crypto++ 5.6.0 SHA-256 in version 0.3.6, generation got broken on the Linux 64-bit build. Version 0.3.8.1 is on SourceForge with the 64-bit binary updated.
Download:
http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.3.8/bitcoin-0.3.8.1-linux.tar.gz/download
Future versions after 0.3.8 will probably require SSE2. Anyone have Pentium 3 or older where this would be a problem?