Hang on SWI

I'm stepping through the GPIO_multi_led_interrupt_armL137 example from TI's quickStartOMAPL1x_rCSL. The code "goes out into the weeds" and never returns from the _call_swi() function call:

static void init_OMAPL137 (void)
{
    // Intrinsic Function; Gain 'supervisor' privileges
    _call_swi(ARM_PRIV_MODE_KEY);

The disassembly window shows this when I single-step (assembly):

00000008:   ???? Memory map prevented reading 0x00000008 [code=0x20000]

or something like this when I try to step over and then suspend the debugger when it doesn't "return":

00ca22f4:   ???? Memory map prevented reading 0x00CA22F4 [code=0x20000]

Any clue what I could be doing wrong?

Thanks.

Steve