Topic on Extension talk:UserGroups

I keep getting this everytime itry to go to "Special:UserGroups" page:

Notice:  Array to string conversion in /var/www/extensions/UserGroups/UserGroup.php on line 834

Stack trace:

  1. {main}() /var/www/index.php:0

  2. MediaWiki->run() /var/www/index.php:43

  3. MediaWiki->main() /var/www/includes/MediaWiki.php:512

  4. MediaWiki->performRequest() /var/www/includes/MediaWiki.php:851

  5. SpecialPageFactory::executePath() /var/www/includes/MediaWiki.php:283

  6. SpecialPage->run() /var/www/includes/specialpage/SpecialPageFactory.php:577

  7. SpecialUserGroups->execute() /var/www/includes/specialpage/SpecialPage.php:522

  8. UserGroup::listGroups() /var/www/extensions/UserGroups/SpecialUserGroups.php:62

  9. array_unique() /var/www/extensions/UserGroups/UserGroup.php:834

Now getting this:

[f0cfc4c8e2b2de05241b3e6d] /index.php?title=Special:UserGroups MWException from line 99 of /var/www/extensions/UserGroups/UserGroup.php: Constructor expects name to be a string.

Backtrace:

#0 /var/www/extensions/UserGroups/UserGroup.php(837): UserGroup->__construct(array, boolean)

#1 /var/www/extensions/UserGroups/SpecialUserGroups.php(62): UserGroup::listGroups()

#2 /var/www/includes/specialpage/SpecialPage.php(522): SpecialUserGroups->execute(NULL)

#3 /var/www/includes/specialpage/SpecialPageFactory.php(577): SpecialPage->run(NULL)

#4 /var/www/includes/MediaWiki.php(283): SpecialPageFactory::executePath(Title, RequestContext)

#5 /var/www/includes/MediaWiki.php(851): MediaWiki->performRequest()

#6 /var/www/includes/MediaWiki.php(512): MediaWiki->main()

#7 /var/www/index.php(43): MediaWiki->run()

#8 {main}