I've posted a pre-release of ClamWin Portable 0.88.5 for testing. This updates ClamWin to the latest version and adds Vista compatibility for both the launcher and the setup routine.
Please give it a try and report back with the results.
Side Note: I compared a compressed version of ClamWin to an uncompressed one for speed in scanning and they performed about the same (the compressed one was maybe a few % faster). So, we're sticking with compressed binaries/JARs, saving us 65% in install size.