Over on the Microsoft Deployment Toolkit Team Blog they have posted some information about some issues wit h Windows 10 Technical Preview builds having some issues with the MDT 2013 Update 1 Preview. Check out the article to see the full workaround, which includes the following steps.
Download the MDT1503.zip file which includes updated scripts and xml files
Grabbing the latest version of the Windows ADK for the Windows 10 Technical Preview
Using the correct version of Windows PE
Fixing HTA by adding the MSHTML.DLL
Check out Aaron’s post to see all of the steps, if I get a chance in the next few weeks I’ll post the required screenshots as a tutorial.