1. Use Copy Raster in 9.3.1 to output to an IMG.2. Select Rectify in 9.3.1 from the Georeferencing toolbar, and output a new raster.3. Open Windows Explorer, navigate to the raster dataset and find the .tfwx file, and change the extension to .tfw. Open ArcMap, select Customize > ArcMap Options > Raster tab, and check on "Use world file to define the coordinates of the raster". Use this last one if ArcGIS 9.3.1 is not available.