Looks like you've checked "Require users to select aPrefix" for that Category and do not have any Sportsbool Prefixes created and associated with that Category. Edit each of your Sportsbook Categories and make sure that option is NOT CHECKED unless you have some Prefixes available for your users to select.
Could be some sort of a new bug cause by changes in the last release. I won't be able to look into it until tomorrow at the earliest. For now, just make sure that option is UNCHECKED so that you can at least CREATE for now (until I can do some troubleshooting). I need to push a maintenance release anyway, so if there is something buggy with this (which there probably is), it will get fixed and pushed this week.
Other than its fixed and will be included in the next release... that's it. Can't tell you when the next release will be. Won't be until everything else that is being worked on for this addon is complete and tested.