RTOS Tiny

I am not able to run the foll. example of rtx tiny

#include <rtx51tny.h>

int counter0;
int counter1;

void main(void)

void job0(void) _task_ 0 { os_create_task(1);

while(1){ counter0++; //printf("%d",counter0); }
} void job1(void) _task_ 1{ while(1){ counter1++; }
} following is the error i get

Build target 'Target 1'
linking...
BL51 BANKED LINKER/LOCATER V5.03 - SN: Eval Version
COPYRIGHT KEIL ELEKTRONIK GmbH 1987 - 2002
"STARTUP.obj",
"rtos.obj"
TO "rtos" Rtx51Tiny
*** FATAL ERROR L210: I/O ERROR ON INPUT FILE: EXCEPTION 0021H: PATH OR FILE NOT FOUND FILE: C:\KEIL\C51\LIB\RTX51TNY.LIB
Target not created