Could you attach the relevant survey, please?

Or enable debug=2 in config.php, reload and send us the error message on screen.

Fatal error: Can't use method return value in write context in /var/www/application/controllers/admin/surveypermission.php on line 596

That line is in the delete function. So the error appears when you delete rights?

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=18374

sorry, one question: in string check for Gid param, but set Uid param is it right?
$postusergroupid = (!empty(App()->getRequest()->getParam('gid'))) ? App()->getRequest()->getParam('uid') : false;

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=18375

Could you pull and check again?

$postusergroupid is fixed in last commit.

error is the same...

$postuserid = !(App()->getRequest()->getParam('uid')) ? App()->getRequest()->getParam('uid') : false;

it's ok now

Is it OK or the same error?

better i think :

$postuserid = (App()->getRequest()->getParam('uid')) ? App()->getRequest()->getParam('uid') : false;
if (! empty($postuserid));

no error

add user : ok
delete user : ok

You can check the commit:

• $uid = App()->getRequest()->getParam('uid');
• $postuserid = (!empty($uid)) ? $uid : false;

Great, I'll mark it as resolved!

Version 2.50 Build 160407 released