You can change the location where Dimension Pro looks for the multisamples folder in the Windows registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Cakewalk Music Software\dp
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Cakewalk Music Software\dp
So, you can move the multisamples folder anywhere you like and then adjust the "Multisamples Folder" value in the registry. Not sure, but you may also need to delete the file programs.lst in C:\ProgramData\Cakewalk\Dimension Pro\Programs to ensure Dimension Pro rebuilds the program list.