Problems with ARM EVB

Hello, I'm using the ARM board with the USB-I2C interface to test the MPU-9150 based evaluation board. The 9150 itself seems ok because I've been able to control it via I2C by other means, but I'm unable to make it work with the ARM interface from InvenSense.

I have two problems. On one hand when I run the application "PC Demo UI Lite" it crashes with the error INV_ERROR_SERIAL_WRITE, ErrorCode=55.

On the other I've tried manually opening the serial port and sending commands directly, but the board only responds to the first command I send every time. For example, if I send "GV" it returns

MPU6050xx V1.3.1 EVB, 07/19/11

or if I send the WHOAMI command with "RD687501" I get RD687568 but then it ignores every other command until I unplug/plug the USB again. To me it looks like a problem with the virtual serial device, but I cannot be sure (maybe I'm just doing something horribly wrong). I'm using Windows XP.

Thanks