Strange error message with the customstyle and group plugins


I have a problem I hope you all can help me with.

I have both the customestyle and the group plugins activated and up until a few days ago, there were no problems. Now when I click on"Groups" under the "Tools" and I get this error message: l error:

Call to a member function getObjects() on a non-object in /home/content/l/e/s/lesbionix/html/mod/customstyle/start.php on line 70

This is line 70:
$customstyle_object = $user->getObjects($metadata_name, 1, 0);

I deactivated, uninstalled, re-installed, then re-activated the customstyle plugin and nothing changed. I still got the same error. When I deactivate the customstyle plugin, the problem goes away.

Any help you could give me would be greatly appreciated!