[Openspace] opening my shape file

[Debra Hevenstone]

I have two files- a shape file w/ point data on zip codes and a another
file w/ my data by zipcode. When I try to open my shp file it tells me
"zip" (my variable of interest) "is not unique"

I'm not quite sure what to do- I did my descriptives in arcview but
there's analysis I need to do either in Geoda or get the spatial analyst
extension from my university. Any clues as to why I can load my shp files
in arcview but not in Geoda?

Thanks,
Debra Hevenstone