Alberto,

There are many mistakes in your code.
The most significant are:

1) There is not the end of your main programme.

2) When you call the subroutines, you have to return from subroutine body properly.

3) You have to save registers in ISR before using them and restore them after using.

4) Define DPL register in the ISR.

5) Set timer registers properly.

And so on...

Please fix the mistakes and try again.

Good luck,
George