I'm not really sure if I understand you. You're trying to use the disk utility on the Tiger install DVD to change the old system (Puma?) on a different hard drive, correct? It's not astonishing that it doesn't work that way. Though I leave it to the pros to explain why.
But in case you try to use the Pume disk utility to change the Tiger system: I would strongly recommed to refrain from using old utilities with newer system. I could definitely corrupt everything on your HD.