CSS: error connecting to target (Beaglebone)

Hi 

I have a setup in which my Beaglebone is connected to an external audio CODEC which most of the time works fine (I have audio throughput :audio->CODEC->Beaglebone->CODEC ->audio..in TDM4). Occasioncally, CSS prompts the following message which forces me to power down the beaglebone and restart CSS:

IcePick_D_0: Error connecting to the target: (Error -151 @ 0x0) One of the FTDI driver functions used during the connect returned bad status or an error. The cause may one or more of: invalid emulator serial number, blank emulator EEPROM, missing FTDI drivers, faulty USB cable. Use the xds100serial command-line utility in the 'common/uscif' folder to verify the emulator can be located. (Emulation package 5.0.569.0) 

Currently I'm just trying to change the gain of the audio stream like this:

/* Copy the buffer (bytes) */
memcpy((void *)txBufPtr[lastSentTxBuf],
(void *)rxBufPtr[lastFullRxBuf],
AUDIO_BUF_SIZE);

//The following code seems not working

p = (short*)(txBufPtr[lastSentTxBuf]);
for(i=0;i<AUDIO_BUF_SIZE/2;i++)
{
p[i] = p[i]>>0; // Changing the shift parameters makes my program crash (not related to the problem itself I think)!!!!
}

Any ideas on why I suffer from this problem?

Cheers

Augmented: I work in Windows 7