RESPECIFIED OR CONFLICTING CONTROL

Hi,
I want to add a delay function to my project. For the reasons specifed in some of the posts in this forum I want to write the delay function in assembly though I am coding my project in C.
Initially I have looked at the link http://www.keil.com/support/docs/146.htm, but as I could not find some of the options specified in this procedure I followed another procedure found in some post. The steps I followed are:
* creating a dummy C file with the structure that I need

#pragma SRC
void delay_asm(int msec)
{

}

*adding the C file to the project
*checking the options "generate the assembler SRC file" and "assemble SRC file"
*compile the project

I have the following statements included in my C file at appropriate positions.
extern void delay_asm(int);
delay_asm(500);

When I tried to build the project it gave me the following fatal error

C51 FATAL-ERROR -
  ACTION:  PARSING INVOKE-/#PRAGMA-LINE
  LINE:    #pragma SRC
  ERROR:   RESPECIFIED OR CONFLICTING CONTROL
C51 TERMINATED.
delay.c - 0 Error(s), 0 Warning(s).

I have seen many posts regarding this issue answered by Andy and Erik but still have problem to resolve it. Can anyone help me resolve this problem?
Thanks in advance