Sorry to have been so vague: as administrator, I checked in .../@@usergroup-userprefs the box "Reset Password" for one of our users and clicked on "Save". This user received a "Password reset request" email. After clicking on the link:
given in this email, the user filled the form:
"My email address is"
and clicked on the button "Set my password". The result was the page ""Error setting password"" with the message given in my OP.
they mention the same problem; however, in the problem description it is specified the person put in an email that didn't exist. in my case this is true - the user put in an email in the reset that didn't exist in the system.
i just did the same action you did: i sent a reset link. i don't know yet if it worked.