YEAH! I've finally found the root cause of the issue and it's NOT Kloxo-MR's related!
If others have similar issues, please DON'T USE THE F**** Google's DNS servers, i.e 8.8.8.8 nor 8.8.4.4, but something else!
Now after changing away from Google's DNS servers in /etc/resolv.conf, i was finally able to flush my queue and the QUEUE IS NOW EMPTY!