This is the part that is very important. To safe the module in the correct folder:
TO INSTALL THE MODULE
1) First install WeatherLink 5.5.1 (or later) or upgrade an earlier version.
If you do not already have WeatherLink version 5.5.1, you can upgrade from versions 5.0 - 5.4, goto: Davis Software Support
2) Download the expansion module here. Save the WuiWlink_1.dll file to your Weather Link Expansion Modules directory:
The Expansion Modules directory is usually in "C:\WeatherLink\Expansion_Modules".
That is... the file needs to go into a directory named "Expansion_Modules" within the Weather Link installation directory. You may have create the "Expansion_Modules" directory if it isn't already there.
3) Quit and restart (or start) the WeatherLink application.
4) Goto the "File" menu and select "Manage Modules".
5) Click the "Add Module" button. Find and select the WuiWlink_1.dll file.
6) Click "okay" several times until all of the dialog windows close.
7) Restart WeatherLink.