Thanks for your feedback! Surely not everything is perfect in the CTP but with your help we can get more things right.
Straight to your questions:
a) Is this the directory where you unzipped the controls or you are referring to the Telerik.Windows.Examples folder?
b) It happens because no startup page has been chosen and it seems blend chooses viewSource.aspx as the default startup page. Right click index.html and choose "Startup", then you can run the solution with F5 and it would start normally. I am not sure why the default starting page is ignored in blend, we will look into that.
c) Yes, this is fixed now. There was a problem with the default values of the control and its panel. It will work if you set the TabStripPlacement value explicitly.
d) I created a project with a TabControl, whose items did not have the Header property set, and it worked fine. Would you be able to send the xaml/project so that I would be able to find out why it crashes?
e) Are you running the demo solution? I am running the demo solution and do not get the error. Could I ask on what machine are you testing the demos? OS and Browser? Theoretically there should be no differences for Silverlight but I would like to test it because if you have encountered the error once we have to make sure it is dealt with.
Thank you again for the feedback!
All the best,
the Telerik team