Modem cutting out

[Myth_man]

I have a Terayon TJ717X cable modem and it has worked great for the last year. Now all of a sudden it resets itself about every 10-20 min. Somtimes sooner but thats the average time. I called up charter, and they tried telling me that it was my conection. I have tried reconecting the cable to the modem to make sure it was tight and everything. I did just add a barrel to the wire, making it longer, but it worked for about 2 weeks then this started happening. Also there was a huge storm the night befor this started happening too. Plz help, i wanna play WoW..:p
Thanks~