crashing after trashing prefs

i've got a voice over which i sent to STP (latest version) which i've put reverb and chorus on to get an "ethereal" sound as specified in the short film script i'm working on. It sounds good but i'm getting a message saying:

Recording Alert, failure occurred when preparing the device(null)

I click ok and carry on.

when i come to save i'm getting a Realtime Effects Warning telling me i need to go to Process - render to action before i can save. I click on the render to action tab but this then crashes the programme and i have to force quit and start again. The recording alert comes up again as well.

I decided to trash the STP pref file (but not the one next to it called STPloops.plist or something) empty the trash and restart my mac, but back in STP nothing seems to have improved.

Any ideas?

I,m on an Intel mac pro with 3GBram.

Seem to have made sense of the issue i was having above post. The Recording Alert pop up appears to be due to using headphones straight from my mac and bypassing the Edirol box under my desk. The process to actions seems to be concerning "tails" when using Reverb or Delay, and the crashing has stopped.