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Why do I receive the error message "c(showbaselevels) undefined r(133)" when running an estimation command in Stata 11?

Title		Error message due to an incomplete update
Authors		Jennifer Rolfes and Jared Stewart, StataCorp
Date		April 2011

Some users may receive the following error message when attempting to run an estimation command in Stata:
     "c(showbaselevels) undefined"The Stata package has two components: the executable and the ado-files. One of the components is out of sync with the other because of an incomplete update. The error can be resolved by completing an update. The update commands will restart Stata, so make sure that any important information is saved before you proceed. If you have a direct Internet connection, type
     . update executable, force     . update swap   It is not necessary to type update swap on a Windows machine, because update executable, force does this automatically.
After the update swap is complete, type
     . update ado, forceAfter the update is successfully completed, your estimation command should work properly.