Fabric/AWS/Boto. Value () for parameter groupId is invalid. The value cannot be empty

I'm trying to use fabric from my windows 7 machine to move my app to an aws server as per this tutorial:

http://ift.tt/1yUZa5b

I've been maneuvering through a lot of snags, but this latest traceback has me stumped. It is throwing an InvalidParameterValue for groupId, but I don't know where that value is supposed to exist. Has anyone seen this before? Can someone help me understand what is broken?

(fabric) C:\Projects\AlmondKing>fab spawn instance

[ec2-52-4-183-5.compute-1.amazonaws.com] Executing task 'spawn'
←[32mStarted...←[0m
←[33mCreating instance←[0m
Traceback (most recent call last):
  File "C:\Users\Adam\Envs\fabric\lib\site-packages\fabric\main.py", line 717, in main
    *args, **kwargs
  File "C:\Users\Adam\Envs\fabric\lib\site-packages\fabric\tasks.py", line 332, in execute
    results['<local-only>'] = task.run(*args, **new_kwargs)
  File "C:\Users\Adam\Envs\fabric\lib\site-packages\fabric\tasks.py", line 112, in run
    return self.wrapped(*args, **kwargs)
  File "C:\Projects\AlmondKing\fabfile\django_fabric_aws.py", line 74, in instance
    env.host_string = _create_ec2_instance()
  File "C:\Projects\AlmondKing\fabfile\django_fabric_aws.py", line 182, in _create_ec2_instance
    instance_type=ec2_instancetype)
  File "C:\Users\Adam\Envs\fabric\lib\site-packages\boto\ec2\image.py", line 329, in run
    tenancy=tenancy, dry_run=dry_run)
  File "C:\Users\Adam\Envs\fabric\lib\site-packages\boto\ec2\connection.py", line 973, in run_instances
    verb='POST')
  File "C:\Users\Adam\Envs\fabric\lib\site-packages\boto\connection.py", line 1208, in get_object
    raise self.ResponseError(response.status, response.reason, body)
boto.exception.EC2ResponseError: EC2ResponseError: 400 Bad Request
<?xml version="1.0" encoding="UTF-8"?>
<Response><Errors><Error><Code>InvalidParameterValue</Code><Message>Value () for parameter groupId is invalid. The value cannot be empty</Message></Error></Errors><RequestID>747fe3b3-9736-4fc3-b0ff-6b
4b3839f86f</RequestID></Response>

EDIT: Amazon provides a short explanation of this error code here:

http://ift.tt/1Dog6Ur

It says:

A value specified in a parameter is not valid, is unsupported, or cannot be used. Ensure that you specify a resource by using its full ID. The returned message provides an explanation of the error value.

I have set the ami name in the project_conf.py file in the following format: 'ami-xxxxxxxx'. I'm not sure if this is the ID that amazon is referring to, but it seems like it is not receiving any value at all.