GIMP: Plug-In Raw.exe not always loaded

The plug-in 'RAW.EXE' for loading/saving raw data files
gets not always loaded.

If Gimp starts the first time after a new installation,
all works fine.
But after the second or third start, the plug-in
is not loaded anymore (not shown in the image type
list of the 'load image' dialog).

Any suggestions how to solve the problem?

Thanks

Hari