This article should help if you try to login using correct Nearmap credentials in Google Earth, but the login window keeps appearing whatever you type, even if you click Cancel.
This can happen if Step 3 of our Google Earth integration instructions was missed. If Google Earth saves your validated credentials to disk, it will try to use the same saved Nearmap authentication cookie every time you try to log in. That may be fine if you haven't logged in elsewhere. However, if you've used the MapBrowser more recently, the original cookie becomes invalid but Google Earth tries to use it anyway. The solution for now is to keep Google Earth from storing that cookie:
On Windows 7
Find Google Earth's cookies file on your hard drive. It is typically at "C:\Users\YOUR_USERNAME\AppData\LocalLow\Google\GoogleEarth\cookies" where YOUR_USERNAME is your Windows username.
Delete this file.
Follow all steps of the Google Earth integration instructions.