I can pretty much assure you that one of your save game files is corrupt. I experienced the exact problem (identical error and same inability to load/save except for the continue option) and was able to fix it by going to the save game folder and moving all of them out of it. I then placed the save game files back into the save game folder one at a time and tried to load the game after each move until I found the one that was corrupt, which I deleted. I'm pretty sure the cause in my case was a crash that occured when an snowstorm caused power to fail while trying to save. Before this and after, my game has been perfectly stable with 0 errors and I am nearing the final battle.

In hindsight, I am also pretty sure it was the most recent save I had made that was corrupt, so you might try to remove this one first and then give it a go. I can't promise you where your games are saved, as I am not at my home PC right now, but in Vista 64 it was a few folders deep for the actual saves under the Drakensang folder in My Games. I can check for details on the exact path if you don't find it when I get home.

So in my case, can the save be classed as corrupt ??

Because when I return to play and look at loading my save, I quite often find another save made at practically the same time called "Continue" - which I certainly didn't make.

Sometimes three saves get created all within seconds of each other - (a) the one I make myself which I name, (b) the "Continue" save created by the game AND (c) an "Autosave" also created by the game.