Ok, had "check for updates" ticked. Got error.
Unticked it - no error!

It seems to be related or I was just lucky.

However - I didn't get the error after clicking "Yes" and closing and reopening poser yesterday.
I did get it again at opening poser today after reboot.
Will report back if I get it back after reboot (but I'm doing stuff now so it'll be later :P)

Silke