Hi,
Got your design to work in that the lcd does work, however there are other error messages relating to the rs232.
As you can see from the picture I have shown the 10k contrast pot, usually if you can see black blocks it means the lcd is working but the program code is not correct, though it could be the contrast is so strong you cannot see the text.
Have also amended a few other things, notice the +5v input, no need for batteries.
The single led had 10k , far too big, 330r only.
You can use hyperterminal to act as a pc for your comms.
Although pins 1,2 &3 of the lcd are connected to power and that 10k pot they are not needed in Isis simulations, the same applies to the crystal and 22pf caps.
Your set the frequency by right clicking the Pic and entering the value in the Edit box.
Not sure, but think the caps on max232 are not needed either.
Afraid I cannot help you on the source code, is it Basic ?