VSP AOFO hasn't changed between versions 10 to 10d. If the problem was that AOFO wasn't installed at all, you would get a different message. The message you're getting indicates that the AOFO VSP driver, VSP.SYS is present and running but the connector is missing or not loaded properly. I would recommend checking the server showing that error for the driver VSP.SYS being loaded. If it is, then use the above mentioned technote to troubleshoot the issue. That Technote covers everything known about the vspapi.dll error.