ERRORS IN RTOS

hey,
i am workin on arm 7 (lpc2148)...i have the following code for rtos bt there are some prblems in compilation of code. so plzz help.
here is the code
#include <LPC214X.H>
#include <rtl.h>
//#include <RTX_Config.h>

void delay(void);

OS_TID tsk_1; OS_TID tsk_2;
// OS_TID init;
unsigned int i;
__task void task1(void)
{ for(;;)
{ IOCLR1=0X00FF0000;
delay();
IOSET1=0X00550000;
delay();
} }

__task void task2(void)
{ IOCLR1=0X00FF0000;
delay();
IOSET1=0X00AA0000;
delay();
}

void delay(void)
{ for(i=0;i<10000;i++)
; }

__task void init (void)
{ tsk_1= os_tsk_create (task1, 0);
tsk_2= os_tsk_create (task2, 0);
}

int main(void)
{ IODIR1=0X00FF0000;
os_sys_init (init);
}

AND FOLLOWING ARE THE ERRORS:
Build target 'Target 1'
assembling Startup.s...
compiling code.c...
compiling RTX_Config.c...
linking...
sa.axf: Error: L6218E: Undefined symbol os_sys_init0 (referred from code.o).
sa.axf: Error: L6218E: Undefined symbol os_tsk_create0 (referred from code.o).
sa.axf: Error: L6218E: Undefined symbol os_clock_interrupt (referred from rtx_config.o).
sa.axf: Error: L6218E: Undefined symbol os_mut_init (referred from rtx_config.o).
sa.axf: Error: L6218E: Undefined symbol os_mut_release (referred from rtx_config.o).
sa.axf: Error: L6218E: Undefined symbol os_mut_wait (referred from rtx_config.o).
sa.axf: Error: L6218E: Undefined symbol os_tsk_self (referred from rtx_config.o).
Target not created
PLZ HELP....