No Display on EB-LM4F120-L35 Boosterpack

I have been trying to get the EB-LM4F120-L35 booster pack to work with the Stellaris Launchpad without success.

I am following the getting started workshop workbook and I initially tried to run the demo program but the display just goes bright white. I then tried the first example in the workshop to display an image file and the result was the same. To keep it simple for trouble shooting I just created the code below to display text, clear the screen then repeat. I can still only get a complete white screen.

Probing the pins with an oscilloscope shows that they are changing state. I also tried a second Launchpad.

Can anyone suggest anything might be doing wrong?

Thanks for any help

Regards
Alastair

#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/sysctl.h"
#include "grlib/grlib.h"
#include "drivers/Kentec320x240x16_ssd2119_8bit.h"

extern const unsigned char g_pucImage[];
tContext sContext;
tRectangle sRect;

void ClrScreen(void);

#ifdef DEBUG
void__error__(char *pcFilename, unsigned long ulLine)
{
}
#endif

int main(void)
{

   SysCtlClockSet(SYSCTL_SYSDIV_4|SYSCTL_USE_PLL|SYSCTL_OSC_MAIN|SYSCTL_XTAL_16MHZ);

   Kentec320x240x16_SSD2119Init();
   GrContextInit(&sContext, &g_sKentec320x240x16_SSD2119);
   ClrScreen();

    while(1)
   {
       sRect.sXMin = 1;
       sRect.sYMin = 1;
       sRect.sXMax = 318;
       sRect.sYMax = 238;
       GrContextForegroundSet(&sContext, ClrRed);
       GrContextFontSet(&sContext, &g_sFontCmss30b);
       GrStringDraw(&sContext, "Texas", -1, 110, 2, 0);
       GrStringDraw(&sContext, "Instruments", -1, 80, 32, 0);
       GrStringDraw(&sContext, "Graphics", -1, 100, 62, 0);
       GrStringDraw(&sContext, "Lab", -1, 135, 92, 0);
       GrContextForegroundSet(&sContext, ClrWhite);
       GrRectDraw(&sContext, &sRect);
       GrFlush(&sContext);
       SysCtlDelay(SysCtlClockGet())
       ClrScreen();
       SysCtlDelay(SysCtlClockGet())

    }

}

void ClrScreen()
{
   sRect.sXMin = 0;
   sRect.sYMin = 0;
   sRect.sXMax = 319;
   sRect.sYMax = 239;
   GrContextForegroundSet(&sContext, ClrBlack);
   GrRectFill(&sContext, &sRect);
   GrFlush(&sContext);
}