[cem] Two different Stata versions, two different cem problems

Dear list, When I try using cem in Stata 10,* *I get the error* "*no variables defined in option treatment(), r(111);" even though my syntax looks fine. (My command was "cem AGCYTYPE POPULATION region lblackproportion, tr (POLYEXAM).") The website <http://gking.harvard.edu/cem/> indicates it works in version 10. When I try using it in Stata 12, I think the program gets a little farther. But I still get the error "cem_weights not found" after the commands: cem AGCYTYPE POPULATION region lblackproportion, tr (POLYEXAM) reg lblackproportion POLYEXAM YP YEAR [iweight=cem_weights] Any ideas how to troubleshoot? My best guess is that I skipped important pre-cem steps and the program is protesting that sort of human error. Perhaps the matched N (672) is too small and so I should simulate more data to produce more matches? Many thanks, Katelyn -- Katelyn Sack, Ph.D. candidate University of Virginia