I doubt that you will have any luck. Premiere 6.5 was ported for both Mac and PC. When it became Premiere Pro (several different names at that point), it was PC ONLY>
PrPro CS 3 was the first version to be X-platform.
You might need to befriend a PC user, with say PrPro CS 3, to Open that Pr 1.5 Project into their program, then Save_As, and use that on the Mac.
Good luck, and sorry for the bad news,
Thanks Bill. I agree. I think the path with the best chance is to convert at CS3 on the PC then try CS6 on the mac.