[GRASS-windows] Location Wizard Problem

[MJ]

I am running the Windows version of Grass 6.4.0 (installed from native
version wingrass-6.4.osvn-r40049-1-setup.exe).  When I try to execute
the following, I have problems.

* Launch GRASS
* On the right-hand side select Location Wizard under Define new location
* Leave the GIS Data Directory field as is but choose a descriptive
name for the Project Location
* Continue to the next page
* Choose Select Coordinate System parameters from a list and continue
* Type in ll for the Projection Code or scroll down the page to find Lat/Lon
* Continue to the next page
* Choose Dataum with associated ellipsoid
When I try to enter a Central Parallel or Central Meridian, nothing
changes occur in the entry boxes.  I can highlight the default zero
values, but I am unable to change them.
If I now click Next, I get the error "Something is Missing.  You must
enter a value for Central Meridian"
The same thing happens if I Choose the Ellipsoid Only option.
How dows one move past this page? Am I doing something wrong, or is this a bug?
Thanks.