The multisamples are only 1/2 the install.
There are also the programs that need to find there way into c:\ProgramData\Cakewalk\Dimension Pro\Programs. This is what the F5 key reads to rebuild the program browser. Note: ProgramData is a hidden directory.
FWIW, depending on which version you install first 32bit or 64bit there are only two possible valid default locations for the multisamples. It would either be "C:\Program Files\Cakewalk (x86)\Dimension Pro\Multisamples" if 32bit was installed first or "C:\Program Files\Cakewalk\Dimension Pro\Multisamples" if 64bit was installed first.
You may be able to verify which location is used by looking in the registry for the "Multisamples Folder" in
32bit version
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Cakewalk Music Software\dp
64bit version
HKEY_LOCAL_MACHINE\SOFTWARE\Cakewalk Music Software\dp