3.7.9 Crashing While Renaming Thumbnails

For whatever reason 3.7.9 is CONSTANTLY crashing while trying to rename thumbnails during a session. It just hangs up and resulting in me having to force quit the application. It continuously does this and is still doing this after trying to trash the preference files too. I am running 10.5.6 Leopard and these are Nikon D3 NEF's so you know as well. If anyone can shed any light on this it would be greatly appreciated.