If the IIS_IUSRS group does not have permission to read/write from the Windows Temp folder, you will see the following error when browsing the web interface:

Unable to generate a temporary class (result=1)

Fix

To grant permission to the IIS_IUSRS group:

1. In Windows Explorer, browse to C:\Windows.
2. Right-click on the Temp folder, and then click Properties.
   The Temp Properties dialog box is displayed.
3. On the Security tab, click Advanced:
   
   The Advanced Security Settings for Temp dialog box is displayed.
4. On the Permissions tab, click Continue:
   
5. Under the Permission entries list, click Add:
   
   The Select User, Computer, Service Account, or Group dialog box is displayed.
6. Click Locations:
   
7. Select the local machine, and then click OK.
8. In the Enter the object name to select box, type IIS_IUSRS, and then click Check Names:
   
   The IIS_IUSRS object name is expanded and underlined.
9. Click OK.
   The Permission Entry for Temp dialog box is displayed.
10. Under Permissions, select the check box to allow List folder / read data:
    
11. Click OK.
12. On the Advanced Security Settings for Temp dialog box, click OK, and then on the confirmation dialog box that is displayed, click Yes: