I searched a bit in the clamav mailing lists and this seems to be a common problem with the new release. It looks like almost all systems are broken that invoke clamav from different users. They created a patch release 0.90.1 that shall fix some of the issues and additionally a change in freshclam prevents that clamav can access the signature databases because they changed the chmod of the files from 0755 to 0700. I added some patches to ISPConfig and test it now. Lets hope that this fixes the problems
