Hello hjq310,

there can be a number of reasons why you get this error message. I have some
questions for you to help me assist you:

1. Which operating system do you use? Windows, Linux, which version?

2. If you use Windows and connect the EFM-03 to your PC, does the
EFM-03 appear in the device manager? If you use Linux and use "lsusb -v",
does the EFM-03 appear in the device list?

3. If you use Windows, did you install the "USB-Driver" from our UDK3 forum
download page?

Cesys UDK3 Download (1.5.1)

If you use Linux, did you install the "Service" script from this download page?

4. Do you use the CESYS UDK3 only to access the EFM-03? Or do you use
software from other vendors to access the EFM-03 as well?

Best regards

Manfred Radimersky
Software Development
CESYS GmbH