Jim,
That texture should show no matter what version you are using; Windows 7, FSX, FSX DX10, or P3D. Nothing is awry in the bgl. If you have the texture on your system then it should display. Just for fun do this:
Make a copy of 057Pierres.dds and put it somewhere else.
In the RTMM Object LibraryFSXP3D\texture folder, change the name of the original to 057pierres.dds.off
Move the copy of 057pierres that you made in step 1 into the texture folder under the main FSX folder.
Reload FSX and then Hang Em High and see if the rocks show.