Information from Open CASCADE support team

Solution to problems with OCCT 6.1 installation on Windows platform.

Open Cascade suggests disabling e-Viewer during installation procedure
In response to numerous user requests complaining of installation problems with Open CASCADE Technology 6.1 on Windows platform Open CASCADE announces that such problems arise in connection with the latest changes in ActiveX controls introduced in a software update to Microsoft Windows XP Service Pack 2 and Microsoft Windows Server 2003 Service Pack 1 (see

ActiveX Plugin, which is no longer supported on Windows platform, is used in e-Viewer OCCT component. As a result, e-Viewer will not work in any browsers under Windows XP SP2 and eventual Windows-based operating systems with the exception of Netscape version 7.1 and earlier.
Open CASCADE suggests that to have OCCT correctly installed e-Viewer should be disabled during installation.
Our company will consider removing e-Viewer from the future OCCT versions or replacing it with other products.