I ended up just starting over, which worked aside from it taking forever to re-make the layer. I'm still not sure what the problem was, since the Manning table was populating just fine.
I'm using HEC-GeoRAS 4.1.1 and ArcGIS 9.3 sp1.
Using HEC-GeoRAS, I am able to create a Manning table for Manning's n values that appears to be correct. I select this table in the Layer Setup and extract the GIS data, but it is not included when I import this data into HEC-RAS.
Any help would...