IPhone :: 4S Is Not Charging When Plugged Into Clock Radio?

So about a week ago, I docked my iPhone 4S into my Sony ICF-C7iP clock radio as I do every evening before going to bed. I bought this clock radio back in August and have had no problems with it at all. However this time, I noticed my phone was not charging. It didn't make the charging beep nor did it show on the display that it was charging. I tried removing it & re-seating it...nothing. I tried rebooting my phone which resulted in the same problem. When I plug my iPhone into either a standard sync cable or an iPhone dock, it charges/syncs as normal.

Suspecting the problem was with the alarm clock, I contacted Sony support. The clueless support rep on the other line suggested I return the clock in exchange for a refurbished one. For a $60 clock, this was more trouble than it was worth, so I decided against it.

I then decided to purchase an iHome iA9 which was sure to work. I just unpacked it and set it up. When I docked the iPhone on it...you guessed it...nothing. It is still not charging. The funny thing is that the iPhone will play music through the iHome with no problems. I had also tried plugging the iHome into a different outlet with no luck either. I am out of ideas. I am left to assume that for some reason, my phone does no longer like charging when docked on to an alarm clock.

how I can get this to work again? I recently upgraded to iOS 5.1 and honestly don't know if that would have anything to do with it. But the likelihood of 2 completely different clock radios exhibiting the same problem is virtually non-existent.

As mentioned, I tried rebooting the phone with no luck. Docking the phone to a standard charging cable plugged into the wall charges the phone fine. Docking the phone on an iPhone compatable dock charges the phone fine. Is the problem with my phone?