I get the error message "RpcOrtho failed: Action failed" when I try to use a particular dem in the RPC Orthorectification Workflow. When I use the default dem or aster, it runs without error. If there some certain format the dem needs to be in? How can I find out more about this error, so I can track down the problem? The dem has this mapinfo- map info = {Geographic Lat/Lon, 1.0000, 1.0000, -149.93536332, -17.45823938, 5.6593862900e-06, 5.6070907577e-06, WGS-84, units=Degrees}coordinate system string = {GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]}