Have you tried moving the interrupt handlers to the top of your program?

It would be easier for members to help you if you posted your code.

Suggestion: make a backup, trim your code down and test for changes (remove 1 logic at a time, it's easier to track down weird stuff).

In-circuit debugging is awesome if your PIC is supported.

I send messages to Microcode Studio Serial Communicator on the PC via RS232 to help debug.

Robert