LE version interfering, maybe?
Dim Pro and Dim LE install by default as two completely independent plugs, so I would say that this is unlikely to be the answer unless OP has taken any actions that would remove their independence - for example, by moving, merging, or deleting samples and folders.
Mr. Desperate, have you confirmed that the specific .rx2 files that the error message references are actually present and correct in the appropriate folder? Bear in mind that unless you have performed the merging of folders (together with the registry hacks) any sample required by any prog for Dim Pro must be in the folder corresponding to Dim Pro, any sample required for any prog for Dim LE must be in its corresponding folder, and any required for both must be in each folder.