1.) Workspace > Preference > Raster Manager > Georeference
2.) Check the working units for Raster File and Sister File
3.) Make sure they are correct
4.) If your raster image has a World/Sister File
5.) Set ”Use Sister File if Present"
6.) Detach raster image
7.) Attach raster image
1.) Try renaming your ERS files so it will use the EWW sister file
2.) Make sure "Use Sister File, if Present" marked in Workspace > Preference > Raster Manager > Georeference.
http://communities.bentley.com/products/3d_imaging_and_point_cloud_software/w/wiki/25017.key-in-to-set-raster-image-inherit-geocs-to-not-inherited
http://communities.bentley.com/products/geospatial/desktop/w/geospatial_desktop__wiki/8499.key-in-to-set-raster-image-inherit-geocs-to-not-inherited