As a follow-up:
After uninstalling 5.01, I restarted my PC and my NVIDIA video and mouse drivers stopped working. I restarted my PC again and both drivers started working. I checked their status and whether they needed updating. Both were working properly and neither needed updating.
I reinstalled P Pro CS5 5.0 and it is working smoothly, no hang-ups when opening the program and no audio hiccups.
I'm virtually dead certain that 5.0.1 had nothing do to with this particular problem - there is only one targeted change that frees the layer restriction on the GeForce cards when it comes to GPU compositing.
What GPU card are you using?
NVIDIA GeForce GT 220