You can do it this way, but it will replace all your settings. I'd rather suggest to manually copy only the file "CacheCDFS" from the CD to your L directory. So only the program file will be upgraded and all settings stay in place.
IMHO you don't need to upgrade the CacheCDFS. From what I heard the original version from the IDEfix package (which comes on the Buddha disk) is identical to the OS3.9 one, only the version numbers have been changed.
Bye,
Thomas