I would recommend that you upgrade to the brand new R1 release of Test Studio. You can download from your Telerik account (screenshot 1).
Since you state that the issue occurs randomly that might meant that you just need to increase the Silverlight timeout in your tests. Here's a video demonstrating how to add a Settings file to your project and use to configure the Silverlight timeout attribute:
All the best,
the Telerik team
Do you think you know all the new features coming out in Test Studio R1 2011?
Think again - we have some surprises and will share them with you in the What's New in Test Studio R1 2011 Webinar on May 12th.