When navigating to the workspace where coverages are located in the Add Theme dialog box, the coverage folders do not display.
The workspace where the coverages are located is an ArcInfo version 6 workspace instead of version 7.
If an 'arcdr9' file is in the INFO directory of the workspace, it is a version 6.x coverage. If an 'arc.dir' file is in the INFO directory, it is a version 7.x coverage. If both 'arcdr9' and 'arc.dir' are in the INFO directory, it is a mixed workspace. ArcInfo can handle mixed workspaces, but Arcview cannot.