I recently updated to 3.0.1.4 and then created a new website. ISPC3 said that it created the site but it didn't really create it because the user group sshusers was missing on my system. Does anyone know what package or process creates the group sshusers? Anyhow, I created the group and then all went well.
The sshusers group is created by the ispconfig installer and should be created also during updates. I added this to the bugtracker so that it gets reviewed for the next release.