I think this could be a hardware problem
If you have not enabled interrupts, then you can place the code anywhere in program memory.
Also since it's running fine on your sim..
Stack pointer is always by default set to 07h, but it's always good practice to initialise it.
Check the EA pin 31 must be tied to Gnd.
Also Check with a 'scope is the oscillator really running.
The reset pin (9) is active high. Reset must be held high for at least two m/c cycles and then brought low.
Good point about the watchdog timer.