I am on Windows 7, Professional 64 bit. Does anyone know what driver this is? I downloaded Parallel tools through Parallels in Mac OSX on my VM.
I may be having a similar issue I've found that when I start Parallels in coherence mode, that I seem to always get a message from Windows telling me that a driver is missing. It provides a link to a parallels support website, which advises me to install the Parallels tools. When I exit coherence mode, I do see - momentarily - message "Press Ctrl + Alt to release the mouse and keyboard", which supposedly is an indication that I need to re-install the Parallels tools, but then, the message goes away. It seems like its related to starting up in coherence mode.
I'd uninstall Parallels Tools, restart Windows and either let it install Parallels Tools at the next boot or force it to do so from the menu. I bet the install did not complete properly and uninstalling, rebooting and then installing again usually does the fix.