Hi
As mentioned in your post if the LED on the Cable modem goes off then better check out the connectivity getting terminated on the cable modem.
If thats not the case i would suggest you to have a look at your NAT overload statement and alter the same..
do add the below statements and try..
No ip nat pool xxxx x.x.x.x x.x.x.x 130 prefix-length 24
No ip nat inside source list 101 pool xxxx overload
Ip nat inside source list 101 interface dialer 1 overload
if you are unable to remove the nat statements do a clear ip nat translations * and try the same...
regds