Yes, this is SharePoint 2010 beta exception.
To do this, follow these steps:
Step 1: Open your IIS.
Step 2: Find Application Pool from your Web Site as I have taken my site as shown.

Step 3: From Application Pool, right click on your application name and click advanced settings as shown.

Step4: Advanced setting dialog box will be opened. Under the Process Model , you will find Load User Profile, set its value to True as shown.

Applying all the above steps, your issue will be fixed.