Sounds like you are running the V08.11.09.493 version. In the latest (08.11.09.674) this was fixed so that you can always hit the Browse button to select the Civil Cell.
In the 493 version, you have to initiate the Place Civil Cells command, then right-click out in the design file. After you right-click in the design file and move your cursor, the Civil Cell Name field will become active again, and you can browse to select one.