Same issue here. The groups do not show up in the Users list. Column is empty.
Any update on this?
Do you have any other plugins installed that might interfere? You’re also supposed to see at least the Registered group in that column as all users are in there by default.
I also use WP-Members and that does indeed conflict with your plugin.
I hope you’ll find a solution because i like (need) both plugins.
Have you been in touch with the developers of WP-Members about this? Maybe they already have a clue to what it might be.
If the plugins do conflict, do you think you could use only one while maintaining the functionality you need?