A thread on the Raven Shield General Discussion Forums describes issues users are having running Rainbow Six 3: Raven Shield due to "Invalid CD key" error problems. This thread and this thread offer suggested fixes, though there are some posts that complain that these have not helped in all cases. Thanks Endgame. Update: Further workarounds and a promise that they hope to address this matter as soon as possible can be found on this Ubi Soft Customer Support Page (thanks HomeLan Fed).