Searching for DAS Server 'UDAS'...
DAS Server 'UDAS' is installed.
DAS Server 'UDAS' is not started yet. Trying to start it now...
DAS Server 'UDAS' has been started successfully.
Warning: Unknown JTAG ID=00000000. Assuming an XC866-4FR device with 16K flash
I struggled for a while with the same problem but without success. Finally decided to search Internet and found some guidance here. I decided to switch mini-USB cable and problem disappeared immediately. Apparently I was using some random cheap low quality cable this time. Took another good thick cable and everything was fine.
Some lesson to learn. Always use good cables and check Internet after a moment if you are not succeeding to resolve problem soon.