Michael,
No worries. I just added Alwin to the same subscription as your account, so you both can post. We have no problem with sharing a subscription if there's a developer or two working on a site
As for the issue you're seeing, it's usually caused by having a required field in Community Builder that isn't being filled out by the user. CB won't let us (JFBConnect) save the user to the database if they're profile isn't complete. Currently, there's 2 ways to fix this:
1) Don't have any required fields in CB that aren't being imported into from Facebook
2) Use the "Full Joomla User" user creation setting in JFBConnect and in the Profiles tab, set the "Show non-mapped required fields" to Yes. This will show the user the required fields during the registration process.
As noted above, we'll be releasing an updated CB profile plugin for JFBConnect over the next few days which will add validation to step #2 above. Unfortunately, right now, we show the fields, but if a user chooses not to fill them out, it can still cause issues saving the user. The updated plugin should correct this.
Hope that helps get you started in determining the cause, but if you don't think what I've mentioned is the issue, we'll help you to investigate further.
Thanks,
Alex