In your 9.3.3 environment, ensure that the HFMApplication Service is using ASP.NET version 2.0.50727.
To verify the ASP.NET version:
Select Start, then Run, type Inetmgr and select OK to open Internet Information Services (IIS) Manager.
Under Web Sites, right-click on HFMApplicationService and select Properties.
Select the ASP.NET tab, and ensure that the ASP.NET version is 2.0.50727. If it is not currently selected, select it from the drop-down menu.