Try this [INTRO] 🗺️ Google Maps With App Inventor! - #2 by SteveJG . It uses the ActivityStarter but note the additional Blocks required.
The Blocks off to the side is to use the example with your gps instead of static coordinates.
Use a variable instead of the Math blocks to use with various coordinates.
Did it work for you? 
Your code can never work. You forgot the decimal point (.) in both the latitude and longitude you typed. :cry in your post