I have had the same problem in both Beta 3 and RC 2: opening the (non-Ajax) Order Entry Sample workspace and selecting the WebApp, then hitting "run" get me the following (I also get this if I try to run it normally):

==========

The page cannot be displayed

There is a problem with the page you are trying to reach and it cannot be displayed.
Please try the following:

Click the Refresh button, or try again later.
Open the localhost home page, and then look for links to the information you want.
HTTP 500.100 - Internal Server Error - ASP error
Internet Information Services

Technical Information (for support personnel)

Error Type:
(0x8002801D)
Library not registered.
/Order_Entry_15_1/Vendor.asp, line 39
Browser Type:
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/532.0 (KHTML, like Gecko) Chrome/3.0.195.38 Safari/532.0
Page:
GET /Order_Entry_15_1/Vendor.asp
Time:
17 December 2009, 16:37:20
More information:
Microsoft Support

==============

Mike