Logic not letting me bounce a really big file "2G limit exceeded" warning

I need to bounce a 45 minute six channel surround mix as a single interleaved 24/48000 PCM file. But when I hit the bounce button, a warning window pops up saying that the file is too big- that the limit is 2 gig. I tried bouncing it again, but as a wav and it bounced successfully. But I really need my mixes to bounce as PCMs, and this 45 minute show is just a test as I'll need to do the same bounce with files twice as long. Might it have something to do with the fact that I have 2 gig RAM?