Time Machine: What's taking up all of that space?

Question

I have a 500Gb External Hard Drive, partitioned in halves for Time Machine and Carbon Copy Cloner.
Recently I had a main hard drive failure. CCC saved my bacon (Oh yes. It's worth having!). The local Apple Boutique restored all of our info to a new 1Tb drive from CCC on the external drive. When I brought the computer home, I popped into Time machine a couple of times to retrieve a few bits of recent info, as CCC was about three weeks old.
On approximately the third visit to TM I noticed that it was only showing a few days of information instead of the year or so that was there previously. At the same time, TM began showing an error message that "This backup is too large for the backup volume.". Although it only shows a few days worth of info to draw from, it says that only 103Gb are available of the 232Gb in that partition.
I'm doing a Disk Utility disk repair right now, but are there other things I should be looking for?
My system is:
Hardware Overview:
  Model Name:          iMac
  Model Identifier:          iMac5,1
  Processor Name:          Intel Core 2 Duo
  Processor Speed:          2.16 GHz
  Number Of Processors:          1
  Total Number Of Cores:          2
  L2 Cache:          4 MB
  Memory:          1 GB
  Bus Speed:          667 MHz
  Boot ROM Version:          IM51.0090.B09
  SMC Version (system):          1.9f4

Answer 1

Thanks Ralph. That is a very useful page.
I found the cause of the problem: A common cause of this is restoring all your data, either to the original internal HD or a replaced one,  depending on the restore method and what version of OSX you're on.  In some cases, everything restored is treated as new, so must be backed-up again.
So TM is recognizing the restored data as new info and wants to stack it up on top of itself again. That explains why there isn't enough room.
My new question is this; the quick and easy would be to erase all of that old TM backup from the partition and start over. Is here no way to change its mind about duplicating all of that data and have TM carry on as normal? With my crappy and intermittent memory it would be nice to be able to go back into TM if something suddenly comes to mind along the lines of, "Hey! Whatever happened to that 'thingy' that we had last fall? I would like to have that again but it got deleted along the way somehow."