C6300BD Portforwarding problems

I've come across my cable modem having portforwarding problems but every one of the pages here so far that I've found to possibly help are full of things irrelivant to my situation. 
I'm attempting to run a minecraft server for me and a few of my friends and I don't want to rely on Hamachi so I set up portforwarding with my modem.  As with the other issues I've seen in regards to this, the portforwarding is correctly done (I've even looked up several tutorials just in case). Every single time I go to check with various portforward checking websites to see if the port was forwarded, nothing. It doesn't register that it is even though I've done everything the way it needs to be done. It managed to work for about a day and that was about it, it stopped after that. I don't know if its an issue with the firmware (Version I have: V2.01.08) and that needs updated or something else. Considering an old router of mine had problems with that and that fixed it. Any light that can be shed on this situation and possibly fix it would be absolutely wonderful!