Sorry, I just saw this. And I'm right now on Linux so I can't confirm, so I might be slightly off here.

There's a setting under keyboard (or terminal, I forget). You might need to change it to 'X11R6'.

Look at section 4.4.3 here: http://the.earth.li/~sgtatham/putty/0.62/htmldoc/Chapter4.ht...

I hope that fixes it for you. Good luck.