I recommend updating to 7.1.1. It's free. This isn't to imply that your problem with crashing-upon-bouncing will be allieviated (I still get this on occasion), but overall it's a much more stable/functional version of LP.
I was trying to bounce a project last night, and Logic crashed on three consecutive attempts. This project involved the use of Garritan Personal Orchestra, which gives me problems a lot of the time. Just for grins, I tried bouncing in Real Time as opposed to in the background like I normally do ..... and the bounce completed!
I think Logic's performance is hampered sometimes by the addition of 3rd party plugins (many apps are that way), which I try to keep minimal as a rule, but this bouncing in Real Time seems to be a passable workaround in this instance.
Hope this is helpful.
solo
PowerMac G5 DP 2.0 Mac OS X (10.4.6) Final Cut Studio, Adobe CS2, Logic Pro 7, MM Studio 8