I have the same Problem
Error: Can only throw objects in src/XF/Db/Mysqli/Statement.php at line 79
XF\Db\Mysqli\Statement->execute() in src/XF/Db/AbstractAdapter.php at line 96
XF\Db\AbstractAdapter->query() in src/XF/Db/AbstractAdapter.php at line 220
XF\Db\AbstractAdapter->insert() in...