Topic on Extension talk:InviteSignup

$wgISGroups = array( 'translator', 'sysop' ); causes a sql error

That code certainly doesn't. Something else may if you haven't run update.php.

Wiki 1.34.2

If i use $wgISGroups

ArgumentCountError from line 456 of C:\inetpub\zoomsoft.de\mediawiki-1.34.2\includes\user\UserGroupMembership.php: Too few arguments to function UserGroupMembership::getGroupMemberName(), 1 passed in C:\inetpub\zoomsoft.de\mediawiki-1.34.2\extensions\InviteSignup\SpecialInviteSignup.php on line 164 and exactly 2 expected

Backtrace:

#0 C:\inetpub\zoomsoft.de\mediawiki-1.34.2\extensions\InviteSignup\SpecialInviteSignup.php(164): UserGroupMembership::getGroupMemberName(string)

#1 C:\inetpub\zoomsoft.de\mediawiki-1.34.2\extensions\InviteSignup\SpecialInviteSignup.php(90): SpecialInviteSignup->getAddRow()

#2 C:\inetpub\zoomsoft.de\mediawiki-1.34.2\includes\specialpage\SpecialPage.php(575): SpecialInviteSignup->execute(NULL)

#3 C:\inetpub\zoomsoft.de\mediawiki-1.34.2\includes\specialpage\SpecialPageFactory.php(611): SpecialPage->run(NULL)

#4 C:\inetpub\zoomsoft.de\mediawiki-1.34.2\includes\MediaWiki.php(296): MediaWiki\Special\SpecialPageFactory->executePath(Title, RequestContext)

#5 C:\inetpub\zoomsoft.de\mediawiki-1.34.2\includes\MediaWiki.php(900): MediaWiki->performRequest()

#6 C:\inetpub\zoomsoft.de\mediawiki-1.34.2\includes\MediaWiki.php(527): MediaWiki->main()

#7 C:\inetpub\zoomsoft.de\mediawiki-1.34.2\index.php(44): MediaWiki->run()

#8 {main}

Are you sure you are running the latest version of InviteSignup?

Yes: InviteSignup-REL1_34-d2f41cb.tar.gz

2020-05-25T18:16:55

That is not the latest version. You can pick up the master or REL1_35 version which to my knowledge are still compatible with MediaWiki 1.34.