If you perform an in-place upgrade of Vista x64 that has iTunes installed, or any program that takes advantage of the GEAR software driver, you will most likely run into this issue. Any CD-ROM or DVD-ROM will have a yellow exclamation point inside the Device Manager of Windows 7.
Thankfully, this is easily fixed without uninstalling or reinstalling iTunes. As of 02/04/09 (version 4.008.5), there is a Windows 7 compatible x86 and x64 GEAR ASPI driver available from Gear Software's
download page.
I'm curious why vendors keep using this driver, because there are plenty of alternatives that provide the same functionality without all the headaches. Why not use the native APIs?