Problem with HDMI feature

I just tried the HDMI feature, but it froze my Thunderbolt completely. I had to remove the battery and put it back to turn on my phone. My phone is pretty new so don't know much about it and can't figure out the reason behind this problem. Has anyone else experienced the same problem? I searched online and asked to other Thunderbolt owners, but found nothing useful. Any idea what the problem is? 

All your answers are warmly welcome.

So I just received my HDMI cable and it doesn't work. My phone keeps crashing or snow appears on the screen. I thought maybe I had a bad cable or the wrong cable, I doubt that  though. Judging by the previous post, should I hold on to this cable?

Well this makes me feel better. I'm not the only one having these problems.

   My 2 dollar hdmi cable works like a champ.  Picture slide show is perfect.  The two movies I put on my phone Avatar and Iron Man 2 look grrrrreat on the big screen from my Thunderbolt.  It's a slick feature and I can take my phone to customers homes, plug it in and display about anything that I need to. 

I used to connect my Thunderbolt via HDMI cable when I first got it in June and it worked fine I watched videos and slideshow... I have not done it since June and the phone had the 2.2 froyo update and then another update last week ...tried hooking it up to the tv today and the HDMI 3 option on the tv shows up but it says no signal detected and the phone does not get the HDMI icon in the notification bar like it used to before the updates back in June...and when I play a video rec with the phone it only plays on the phone as if nothing is connected....when I unplug from tv the HDMI 3 option does not show up which tells me I am looking at the correct HDMI output just the phone is not recognizing that it is connected now after all the updates...any ideas what the problem is or has anyone experienced this?