App Inventor Compile Error Login Template WordPress

Solution: 

To know which block is creating the error:

1. Export your app as .aia (Project/Export selected project (.aia) to my computer): the .aia should be created even if you get an error when building the .apk.
2. Then change the extension of your .aia to .zip
3. Go to the folder Your_app_name\src\appinventor\ai_your_username\Your_app_name
4. Open the .yail file Go to the line indicated in the error ex for you line 75 (or 19)

The “words” in the first parenthesis will tell you which block it is.