I just rebuilt my laptop with Win7 x64 on an SSD drive and Directory Opus is one of the first utilities to get installed. I noticed when I pin Opus to the start bar, the icon changes from the standard Opus icon to an icon that looks like a page with the upper right corner folded down. If I un-pin Opus, the Icon changes back to the normal Opus version. I was going to re-install Opus but wondered if there was another fix for this problem.
Try clearing the icon cache with this tool: