The Easysoft ODBC-Salesforce Driver Setup program updates the PATH environment variable to enable the Easysoft ODBC-Salesforce Driver libraries to be loaded.
If you attempt to configure a Easysoft ODBC-Salesforce Driver Data Source from within Server Manager, you will get error "The program can't start because essupp.dll is missing from your computer" if Server Manager was running prior to starting the Easysoft ODBC-Salesforce Driver Setup program. This is because the updated PATH value will not be available to applications run from within Server Manager.
To solve this problem, exit and then start Server Manager again. You will then be able to configure Easysoft ODBC-Salesforce Driver Data Sources without getting this error.