Judging by this:
Matched Data: ()=!( found within...
It looks like it's coming from the test URL used on the URL Structure option - the QA_URL_TEST_STRING constant defined in qa-base.php and used in admin/admin-default.php.
Not sure if there is a way to fix that in Q2A, the whole point of the string is to check that URLs with special characters work.
Do you have LDAP on your server? It's not part of Q2A so the best solution is probably to turn off that security option. You may need to ask your host.
Otherwise you should be able to work around it by commenting out the foreach block at line 984-994 in admin/admin-default.php.