The problem with PBP interrupts is they are not processed until there is a break in the code, as in if you have a PAUSE in your code PBP will wait until the PAUSE is finished before the interrupt is handled. ASM interrupts do not wait.

To make it all easy Darrel gave us this
http://www.picbasic.co.uk/forum/showthread.php?t=3251

If that does not work you may have a problem else where.