Hey everyone... we found the issue with this. So sorry for the problem. The 2.7.3b update added a new feature option for enabling partial payments for the user panel in each event. For a new install, this new database field was being added, but for upgrades, it was not creating the new database field... which then caused the problem you were having. We have just updated the 2.7.3b package with this fix. Please download from My Orders then reinstall. The reinstall will update the database for you now.
We are working on a few more enhancements and will have a 2.7.3c package available shortly, but for now, we just updated the 2.7.3b package to get this fixed resolved right away. Thanks for your patience on this.
I am now running the 2.73c package from March 2nd. and as posted above, it seems to have fixed the problem. There may be an issue creating events with repeats under some circumstances but I can upgrade later after the DTR team works that out.
We will have our site go live with DTR 2.7.3c. We are continuing with our template changes on DTR and hopefully will have our updated site live this weekend.
I am very happy with the support I have received from the DTR team.
Also, thanks to the the helpful postings in this thread that helped me with a temporary workaround for the problem and helped and get joomla debug turned on so I could report the SQL error for the DTR team.
Thanks Tom... got your note about repeating events and will follow up. There is not an issue here... I can pretty much bet without even looking that you are missing one detail which is keeping the repeating events from being created. I'll hit you up on that.