You're getting this error because you are apparently running on a 32bit system and the Android emulator is designed to operate best in a 64 bit environment. The only real solution is to install a 64bit operating system.
If your hardware doesn't support 64bit or you can't reinstall right now you can temporarily bypass the problem by passing
when you start the emulator from the commandline or by setting ANDROID_EMULATOR_FORCE_32BIT to true in your environment (as the error says). You can do this by running:
From a terminal. Add the text:
to the end of the file and save and close it. I can't test it right now but you'll either need to run
from the terminal or restart for the changes to take effect.
Try launching the emulator.
It is highly recommended that you install a 64bit operating system to continue your Android development because Google will eventually remove the 32bit binaries which will cause your emulator to stop working. Android itself is also moving towards a x64 architecture, so by staying with 32bit you will get left behind very soon.