I'm puzzled by this...
When you reinstalled FCS 2 did you wipe the app's and content from your drive first or just install over the top of them?
Also, found this on the Apple Discussions from June. most users managed to get the templates working by simply re-installing and updating to 6.0.2 or above.
One user had to take the following steps:
* I trashed the Motion application (even though it was updated to 3.0.2).
* I reinstalled just the Final Cut Studio files using the Final Cut Studio install disks (didn't install any of the extra stuff)
* went to Software update, which offered to update both the Pro Applications Update AND Motion 3.0.2. This time, I ONLY had it install the Pro Applications Update, NOT Motion.
* After it installed, I opened FCP 6.0.3, still got the black screen with the Master Templates.
* I went back to Software Update and THEN installed the Motion 3.0.2 update.
* rebooted and opened FCP, and the Templates were finally working again.
Let us know if this helps.