Error message at the bottom of everypage:

Notice [PHP]: Only variables should be assigned by reference in file kernel/profile.php line 94
Notice [PHP]: Only variables should be assigned by reference in file include/common.php line 215
Notice [PHP]: Only variables should be assigned by reference in file kernel/config.php line 239
Notice [PHP]: Only variables should be assigned by reference in file kernel/config.php line 239
Notice [PHP]: Only variables should be assigned by reference in file kernel/groupperm.php line 229
Notice [PHP]: Only variables should be assigned by reference in file modules/system/admin/preferences/main.php line 39
Notice [PHP]: Only variables should be assigned by reference in file modules/system/admin/preferences/main.php line 45
Notice [PHP]: Only variables should be assigned by reference in file kernel/module.php line 1447
Notice [PHP]: Only variables should be assigned by reference in file kernel/module.php line 1447
Notice [PHP]: Only variables should be assigned by reference in file kernel/module.php line 1447
Notice [PHP]: Only variables should be assigned by reference in file modules/system/admin/preferences/main.php line 53
Notice [PHP]: Only variables should be assigned by reference in file kernel/groupperm.php line 229
Notice [PHP]: Only variables should be assigned by reference in file include/cp_functions.php line 41
Notice [PHP]: Only variables should be assigned by reference in file include/cp_functions.php line 50
Notice [PHP]: Only variables should be assigned by reference in file kernel/groupperm.php line 229
Notice [PHP]: Only variables should be assigned by reference in file include/cp_functions.php line 58
Notice [PHP]: Only variables should be assigned by reference in file include/cp_functions.php line 90
Notice [PHP]: Only variable references should be returned by reference in file kernel/module.php line 172

type part of the error message into the search block.

will help you even a little more:
go admin menu - > preferences -> general settings

Debug mode is php debug in your case, set it to off.