use the sys/bios task demo issue

I am a sys bios beginner.when I create a  project use the task demo in ccsv4.step into Task_sleep(10) function is not return . program is dead.

i cannot find the issue.

/*
 *  ======== main.c ========
 */

#include <xdc/std.h>

#include <xdc/runtime/Error.h>
#include <xdc/runtime/System.h>

#include <ti/sysbios/BIOS.h>

#include <ti/sysbios/knl/Task.h>

/*
 *  ======== taskFxn ========
 */
Void taskFxn(UArg a0, UArg a1)
{
    System_printf("enter taskFxn()\n");

    Task_sleep(10);

    System_printf("exit taskFxn()\n");
}

/*
 *  ======== main ========
 */
Void main()
{ 
    Task_Handle task;
    Error_Block eb;

    System_printf("enter main()\n");

    Error_init(&eb);
    task = Task_create(taskFxn, NULL, &eb);
    if (task == NULL) {
        System_printf("Task_create() failed!\n");
        BIOS_exit(0);
    }

    BIOS_start();     /* enable interrupts and start SYS/BIOS */
}