i was very sure about that but still i wnted to confirm that is why i asked you for the queries…
i assumed that you are using KEIL compiler… and if not my suggestion to use that..
there might be two thing one is yoiu havn’t included the #include<reg51.h>
in your code…
or if you have included then either the keil have not installed properly or go to the drive in your computer where you have installed keil software, the go to keil folder open it open C51 named folder then to ASM there you find the all hedder files your software is supporting,,, check REG51 is present of not…that file must be there…
if its not there either downlad that file or downlaod other keil version and try…
still if you get any problem let me know….
download keil from here:
http://worldforfree.net/software/1146159878-keil-c51-v901-compiler-uvision-4-ide.html