I use PRE 9 since last january on my Mac and my laptop Vista.
I get media from my DV and HDV cameras, and also from an AVCHD cam used by
a friend. Same from the HD camera used by my Daughter, a bit more complex
if I remember.
Often, I acquire media via the 'acquisition' window (I use the fench version).
On the iMac, I load videos with iMovie too, used as back-up. And in some cases
the behaviour is different, mainly due to the lack of MPEG2 codec that Apple does not
install on the machine (you can buy it on apple store..).
I'm not sure what's going either (or what your computer specs are or what model of camcorder your video is coming from). But I use version 10 on my dual-core iMac (OSX Lion) and it runs flawlessly!
Have you contacted Adobe Tech Support?
Welcome to the forum.
Can you list the specs. of your Mac, please?
As for PrPro CS 4, have you updated that program? There were at least 3 upgrades, and the last two not only fixed some Bugs, but added quiet a bit of file type support. For instance, I think that support for VOB (DVD) Import was added in the second one, and some direct DSLR support in the third. For more details on working with PrPro CS 4, there is an active FORUM for earlier versions (CS 5.5 is the current one).
Also tell us the format of your video and what model of camcorder it came from.