Either declared as WORD or value stated in the command, if > 255 the program will hang....

But I did some additional tests with value from 256 up to 999; from time to time, the program will resume. Nevertheless, the value expressed in milliseconds is never corresponding (time is far far longer, can last over minutes!).

Values over 999, will make the program never resume.

My circuit is simple:
PIC16F690 - 4MHz Xtal
GPS module GLOBALSAT em-406a + 10k pull-up on TX
LCDisplay in 4bits mode

I use MCS standard 3.0.0.5 + PBP2.50C.