I dont do 16Fs, from what you describe, you are overlapping the interrupt vector and the program memory area, i would suggest performing a call to the interrupt program in the interrupt vector and writing the vector response elsewhere( after the main program for example). Also you can try putting a separate ORG for the main program as well rather then a label as you have done. For some reason your program is not compiling on my PC, otherwise would have tested them for you.