We have lost a two inch wide black section on the right side of the plasma panel, any ideas

Most likely the lower buffer board " E " needs to be replaced. Right now I'm working on repairing a 42" Samsung plasma HP-R4272. The Service manual for that TV says for trouble shooting for that problem is the lower buffer board " E ".
Best to find the correct Service Manual for your TV over the internet to get the correct part number for replacement. The Service Manual should be less than $20.

I black strip about 3 inch of disply left side and the rest working ok

Well, I have the HPR 4272. I bought it 3-4 years ago, it says it was mfg'd in 2006, according Samsung tech support. Anyway, this is April 2010, and I just got a black bar, vertical, on the right side of the screen that doesn't work anymore. I was told buffer board problem by the authorized TV repair guy. He says there are 2 total (3 in the 50 inch versions), and that the only way to fix is to come over and replace the whole glass screen - he says the buffer board is built in? Anyway, he's saying about $1K cost - hell, I might as well buy a new TV at that price - is that what other people are hearing on this issue? What a rip off!!!