EuCon suddenly broken - Eucon client can not access the bonjour service

[noiseboyuk]

Long time stable system (specs below). After a restart today, suddenly EuCon has fallen off a cliff with the error message in the title here. After googling, I see Bonjour has something to do with Apple and iTunes. I've uninstalled both EuCon and iTunes, restarted, reinstalled, restarted, no change. I then stopped the autorun EuCon services and fired them them off one by one in a batch process (historically I've had problems with them falling over themselves), and everything updated to the latest version. All to no avail - MC Client always produces the above warning when trying to run, and EuControl cannot launch.

Any help very very gratefully received.

EDIT - forgot to say, have tried a system restore, but the restore fails citing that it "failed to replace the file (C:\Program Files(x86)\Euphonix\EuCon\Cubase 5.5\components) with its original copy from the restore point."