Catalyst can be installed on a Windows 64-bit operating system. The installation will proceed normally and install Catalyst to the Program Files (x86) folder.
Microsoft issued knowledgebase article 2269468 on compatibility of Office 2010 64-bit products where 32-bit Office products have already been installed. Since Catalyst is a 32-bit application, you must use the Access 2010 32-bit version (or later version of Access). The 64-bit versions of Microsoft Office and Access are not compatible with Catalyst. Further, the 32-bit versions of the Access cannot be installed on a machine where Office 64-bit products have already been installed. The article recommends installing the 32-bit Office product on machines with 64-bit operating systems to preserve compatibility with 32-bit applications.