Being away from my system I can't give specifics but I found similar issues with the gpsd rules file conflicting with other USB serial devices. I had to comment out the specific gps device rules that were conflicting.
Furthermore there also is a conflict with the Davis Vantage device which grabs a port, even though I do not have a Davis Vantage, and makes connecting my Esatto focuser (IIRC) fail. I thus has to remove the 99-vantage.rules file to fix the issue.
I can provide specifics when I get back home, if needed.