I messed around trying to get ActiveState Python 2.7 so I'd have everything the same as you and others. I had run into a similar issue with my
python.org version implementing Jon Larssens' BoAMFP (which handles all my non-brokerage accounts). I finally gave up and ran pip to install dateutil. First time I executed F2O.py it ran perfectly. Since I don't have a copy of the Fidelity position and history CSV files from 1/22, I was amazed that it produced OFX files using the F2O_DBgather.csv I created from the 1/22 OFX files and then Money updated perfectly.
I can't thank you enough for all your efforts, both for the group and for me personally. Your DB_gather.py and F2O_beta12 are working perfectly with options.