Code:
INTCONbits.GIE = 0;
This will definitely cause the red-light-of-death it turned off for any length of time. The GIE bit is also known as GIEH -- you've just disabled ALL interupts including the high priority interrupt that exchanges data between the master processor and user processor. If you wanted to disable all user interrupts you'd use GIEL bit instead.
See pg 121 in the PIC18F8722 manual (DS39646B;39646b.pdf)