Nicky,
Download the copy of Cloud_V6 from this link (http://forums.sketchucation.com/viewtopic.php?f=323&t=1537)and give it a try again. The version on Ruby Depot is different, or should I say it didn't work for me but this version did.
I think I have figured out why I was having a problem with the DEM data I was creating from scratch. Once I have it all worked out I will post my findings. Basically I figured out that the X, Y and Z data seems to need to have a decimal point and a value after it. I was able to get it to work with the attached data file.
Let me know if it works for you.
JP