400 Bad Request when using solrcloud

Can anybody help me i want to create a solrcloud on aws using this code http://ift.tt/1GyTAQl i try to build using cmd [fab demo:demo1,n=1] getting below error I'm getting this while pulling instances after connection to amazon server.

ERROR: boto.exception.EC2ResponseError: EC2ResponseError: 400 Bad Request

Appreciate your help

thanks in advance

root@adminuser-VirtualBox:/opt/febric/solr-scale-tk# fab demo:demo1,n=1
Going to launch 1 new EC2 m3.medium instances using AMI ami-8d52b9e6
Setup Instance store BlockDeviceMapping: /dev/sdb -> ephemeral0
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/fabric/main.py", line 743, in main
    *args, **kwargs
  File "/usr/local/lib/python2.7/dist-packages/fabric/tasks.py", line 427, in execute
    results['<local-only>'] = task.run(*args, **new_kwargs)
  File "/usr/local/lib/python2.7/dist-packages/fabric/tasks.py", line 174, in run
    return self.wrapped(*args, **kwargs)
  File "/opt/febric/solr-scale-tk/fabfile.py", line 1701, in demo
    ec2hosts = new_ec2_instances(cluster=demoCluster, n=n, instance_type=instance_type)
  File "/opt/febric/solr-scale-tk/fabfile.py", line 1163, in new_ec2_instances
    placement_group=placement_group)
  File "/usr/local/lib/python2.7/dist-packages/boto/ec2/connection.py", line 973, in run_instances
    verb='POST')
  File "/usr/local/lib/python2.7/dist-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>ca03b6d4-ce0e-46d3-99e3-ccad4a43c4ff</RequestID></Response>