Hi,

Have you verified that the PIC is running at the desired (4MHz) speed? OSCCON=$60 doesn't look quite right to me.
Have you checked that the serial connection works and that you can recieve data in a non interrupt driven way, ie by using HSERIN for example?

Not sure if it's related or nor but generaly you don't want DT-Ints to reset the interrupt flag because it gets reset automatically by the hardware when the RCREG is read.

/Henrik.