GrLib "WidgetProcess" and TiRTOS based on MPU9150 RTOS example

Hello together,

i´m trying to combine the TiRTOS with the MPU9150 RTOS example.

- TM4C123G DevelopmentBoard
-CodeComposerVersion V6
-TiRTOS for TIVA-C V2.0.2.36
-TIVAWARE 2.1.0
- Dani Rebollos Touch Display Boosterpack2 and driver http://danirebollo.es/index.php/blog/item/23-lcd-boosterpack-v2

I stripped everything but the dataCollectionTaskFxn(). That means i removed the Tasks and Inits for Write to SD Card and USB.
When i call

WidgetMessageQueueProcess();
the system crashes. I call it inside the dataCollectionTaskFxn(). If i comment it out and use just the drawRectangle and DrawString functions everything is ok.

I have worked through the RTOS Workshop, but i can´t figure out what i´m doing wrong. Probably i lack some particular information from the workshop (there where quite a lot of infos^^)

Finally i wanted to ask, what i have to consider, to solve this. I think this approach is, what a lot of others do.

Cheerio!

Following is my dataCollectionTaskFxn().
It reads the first ACC Data and writes a current averaged value and a smallest and a biggest value to the display.

Void dataCollectionTaskFxn(UArg arg0, UArg arg1)
{
	signed short tmp = 0;
	static signed short oldNeg = 0, oldPos = 0;
	char c1, c2;
	static int aveCntr = 0, ave = 0;
	/* Use the 1st instance of MPU9150 */
	mpu = MPU9150_init(0, Board_I2C_MPU9150, I2C_MPU9150_ADDR);
	if (mpu == NULL) {
		System_abort("MPU9150 could not be initialized");
	}

	while (1) {
		Semaphore_pend(sampleData, BIOS_WAIT_FOREVER);

		if (!MPU9150_read(mpu)) {
			GPIO_write(Board_LED0, Board_LED_ON);
			System_abort("Could not extract data registers from the MPU9150");
		}
		else
		{
			c1 = mpu->data[4];
			c2 = mpu->data[5];
			tmp = 0;
			tmp |= ((c1<<8) + c2);
			ave += tmp;
			if(aveCntr == 7)
			{
				ClrScreen(ClrWhite);
				tmp = ave >> 3;
				if(tmp < oldNeg) oldNeg = tmp;
				if(tmp > oldPos) oldPos = tmp;
				ave = 0;
				GrContextFontSet(&sContext, &g_sFontCm30b);
				convertNumberToString(tmp,stringNbr);
				GrContextForegroundSet(&sContext, ClrRed);
				GrStringDrawCentered(&sContext, stringNbr, 6,GrContextDpyWidthGet(&sContext) / 2, 160, 0);

				convertNumberToString(oldNeg,stringNbr);
				GrContextForegroundSet(&sContext, ClrRed);
				GrStringDrawCentered(&sContext, stringNbr, 6,GrContextDpyWidthGet(&sContext) / 2, 185, 0);

				convertNumberToString(oldPos,stringNbr);
				GrContextForegroundSet(&sContext, ClrRed);
				GrStringDrawCentered(&sContext, stringNbr, 6,GrContextDpyWidthGet(&sContext) / 2, 210, 0);
				aveCntr = 0;
			}
			else
			{
				aveCntr++;
			}

			WidgetMessageQueueProcess();
		}
	}
}