Comment 4 for bug 1015828

There was a regression in 0.97.5+dfsg-1ubuntu0.12.04.1 that prevented it from being installed properly on new installations. 0.97.5+dfsg-1ubuntu0.12.04.2 was quickly released to solve the issue. You may need to uninstall clamav completely before attempting to install 0.97.5+dfsg-1ubuntu0.12.04.2.

Although, looking at the DpkgTerminalLog, that may not be the exact issue you are having, as it would seem clamav-milter is failing to start. I'm not quite sure why it didn't get updated at the same time the other packages did.

Could you try removing clamav completely and reinstaling it?