Following on from my original post, an update of the Solar Radiation Technology Preview has just been released to the Autodesk Labs site. You can download it from here:
Solar Radiation Technology Preview
For those who have been having problems with the original due to the comma separator used by your O.S, it will be interesting to hear if the problem continues with this update or not.

Hi Simon
Thanks! Yes now it works without switching the regional settings.
Do you know if its possible to save the analysis in the View. It dissapears evry time I reopen the project. Or is this a limitation of this Preview application.
Peter
Posted by: Peter Tranberg | Monday, 05 July 2010 at 02:29 PM
Hi Peter,
That is good to hear.
To save the analysis you will need to use the 'Save to Project' option on the Output tab, this will create an image,it will not save the analysis results in the 3D View.
Cheers,
Simon
Posted by: Simon Gillis | Thursday, 08 July 2010 at 11:16 AM