Hi,

If the this piece of code is exactly what you have, then you have a mismatch between your push-es and pops. There are 6 pops but only 5 pushes! Also, the last byte pushed is DPL, but the first byte popped is DPH.

About the 'depth': every byte you push requires one byte on the Stack. If you push the DPTR, it requires 2 bytes. Simple, eh?
It gets a little more complicated, though: Every CALL and interrupt also uses Stack space to store the return address. The maximum depth to which you can push bytes onto the Stack is therefore dependant on: 1. the size of the Stack and 2. the level of 'nesting' of subroutines and interrupts.

Best regards,
Rob.