We had a problem with Raster Design 2010 (full version, not the Object Enabler) and Civil 3D 2010 that prevented us from using it for quite a few months. I can't remember what the solution was (removing/changing directories in the PATH statement, loading aecilb51.arx with APPLOAD, installing from DVD or HDD instead of a deployment) and unfortunately our Autodesk tech on the IT side is gone, but it wasn't seamless and took months to find a solution. This was on an XP Pro 32-bit machine. On my home PC, Win7 64-bit OS, the MSI file had to be changed so as to ignore the 64-bit OS and install as if it were 32-bit. Again, not seamless but not so hard to troubleshoot.