How to report size of folder on C:\

Hi Guys

I am trying to find out the size of all my users C:\Data folder.

I come across the below and have tried to tweak it for my needs but no joy as yet.

http://community.landesk.com/support/docs/DOC-17790

Has anyone used Landesk to do something similar? Ideally it would be nice to report this in the inventory but if there is other methods it would be great to know.

Will be running on x64 bit machines.

Thanks in advance.