I followed your instructions to the letter, scook, and re-installed Dim Pro and the expansion packs, but it's still the same. Then, today, I downloaded Dim Pro and the Expansion packs again without any AV running (after uninstalling them first), and re-installed them and it's still the same. So, I give up. Thanks for trying to help, though. I appreciate your efforts.

>If the error is a dialog with the title "Multisample Not Found" note the sfz file name in the dialog.
 
One thing I've just noticed: The error message I get is, e.g., "HH_bonusbeats_100_04.rx2 not found." Is it supposed to be an .rx2 file? Shouldn't it be an .sfz file? Or is the .rx2 a slice of the .sfz, or something?

Also, as I noted earlier, none of the .sfz files in the C:\Program Files\Dimension Pro\Multisamples\70 - Drum Loops folder in Windows Explorer appear in the Program Browser of Dimension Pro, and vice versa - none of the files in the Program Browser of Dimension Pro appear in my Multisamples folder.

Another thing which seems strange to me is that besides the Multisamples folder in C:\Program Files\Dimension Pro, there is another Multisamples folder just sitting on the C:\ drive (i.e. C:\Multisamples). C:\Multisamples has only 15 folders, compared to the C:\Program Files\Dimension Pro folder which has 39 folders. They are the same folders, though, just not all of them.

I made sure that none of these existed before I re-installed, but they have re-appeared exactly as before.

I might call tech support, although I'm in Australia so I assume it will be an expensive call. Also, I'm really only interested in one file, which is HH_BonusBeats_90_01, which I used in one of my songs a couple of computers ago, when the file was actually working for me. I think it hasn't worked since the X1 upgrade.

Maybe some of this information gives a clue to the issue?

I can't load it because it doesn't appear in the Program Browser of Dimension Pro.
 
And for those that do appear, all I get is the error message: Multisample Not Found. And in the error message it lists an rx2 file, not an sfz file.

There are two categories of files that you have to keep separate in your mind : Multisamples and Programs
 
1. Multisamples :
 
   - reside in the Multisamples folder (wherever you put it  --> you have the choice)
 
   - this folder contains the *.sfz's and their samples (wav, flac, etc)
 
2. Programs :
 
   - reside in C:\ProgramData\Cakewalk\Dimension Pro\Programs   (I hope this is right, I'm not at my daw)
 
   --> you don't get the choice to put these elsewhere
 
   - this folder contains the program files  *.prog's
   - each program contains DimPro settings and pointers to the sfz and sample files for its Elements.
 
What shows up in DimPro's browser is only what is found in the Programs folder.
 
Thanks for the clarification. I thought it was something like this, but wasn't sure. It's the programs in the Program Browser of Dimension Pro which are giving me the error message of Multisample Not Found when I try and load them (this is only for the Expansion Pack 2>Grooves folder programs). However, the error message says that the file that isn't found is an .rx2 file (which has the same name as the program). I assume that the .rx2 file is an element of the program (?). However, when I search for these .rx2 files on the C: drive, they are not there. 

Luke73
It's the programs in the Program Browser of Dimension Pro which are giving me the error message of Multisample Not Found when I try and load them (this is only for the Expansion Pack 2>Grooves folder programs). However, the error message says that the file that isn't found is an .rx2 file (which has the same name as the program). I assume that the .rx2 file is an element of the program (?). However, when I search for these .rx2 files on the C: drive, they are not there. 

The programs using REX files are named for the REX file in element 1. The default location for the REX drum loops is "C:\Program Files\Cakewalk\Dimension Pro\Multisamples\72 - REX Drum Loops". The HH files are in a subdirectory called "Hip Hop Beats".

When searching for programs, I use Windows Explorer. AutoHotkey can make Windows Explorer a handy replacement for the DimPro browser adding a script
run explorer.exe "c:\programdata\cakewalk\dimension pro\programs"
 
I do not understand the two mulitsample directories, DimPro only supports a single multisample directory. The default is either "C:\Program Files\Cakewalk\Dimension Pro\Multisamples" or "C:\Program Files (x86)\Cakewalk\Dimension Pro\Multisamples" depending on whether the 32 or 64bit version of DimPro was installed first. The location may be changed by modifying the "Multisamples folder" in the registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Cakewalk Music Software\dp
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Cakewalk Music Software\dp

There is a learning curve to AutoHotkey. The short answer is run AutoHotkey, then right-click on the "H" icon in the notification area and "Edit this script". The default AutoHotkey script file opens in notepad. There are a couple of examples. Add
#d:: run explorer.exe "c:\programdata\cakewalk\dimension pro\programs"
to the file and save it.
The right-click the "h" icon again and "Reload this script"
Anytime the Windows-d key is pressed the Windows Explorer will open at the DimPro programs.
 
Of course you will either need to add Autohotkey to run at machine start up or make sure it is running before launching SONAR or DimPro to use the script.
 
The REX files must have been part of the second expansion pack at some time at least according to the program location. The actual location of the REX files is a guess on my part based on my installation.
 
As far as two multisample directories, it could be a permissions issue, IDK. Only one is used by DimPro so you have some decisions to make.