>I currently check for the existence of a specific file in a specific location to determine if a "module" is installed.
>
>RETURN file(_screen.mvApplication.DataDirectory + "PEOPTION.DBF")
>
>How can I accomplish the same thing in SQL Server?

You can used the SQLTABLES() function in VFP to return a list of all user tables. You'd simply have to use a locate statement to see if it exists. See documentation for details.