Depending on which aspect of WinTariff you want to configure, you can use the options available in the Settings section (found on the top-side bar). In case you're seeing an error for long distance calls, press the Tariffs button from upper bar, open the desired scheme select the area that you're interested in and edit its Access code to the corresponding value. WinTariff also has a pretty comprehensive Help section, which could help you with these issues.
In case you need additional information regarding the application, I recommend contacting the developers directly using this email address: phonewarez@gmail.com as they will surely be able to answer all of your questions.
