Which device and out of curiousity, what's up with the slightly odd baudrate?

Well nothing and intermittent isn't quite the same :-)
Are you SURE the serial data is actually getting to the correct pin on the PIC? Have you checked? Scope, logic analyzer?

Write up a simple program to make sure you have a working serial connection both ways, something like:
Code:
Main:
   HSERIN 5000, timeout,[char]
   HSEROUT[char]
Goto main

Timeout:
   HSEROUT["Nope, not this time. Lets try again",13]
Goto Main
EDIT: Sorry, didn't realise serial was over the BT...I guess data IS comming to the correct pin then.