could not initialize global default settings certificate name must be lower case

[thdotnet]

Hi, I'm trying to create an azure vm following the command:

$puppet azure_vm create --management-certificate pem-or-pfx-file-path --azure-subscription-id=your-subscription-id
--image b39f27a8b8c64d52b05eac6a62ebad85__Ubuntu-13_04-amd64-server-20130501-en-us-30GB --location 'west us'
--vm-name vmname --vm-user username --password ComplexPassword --puppet-master-ip 198.62.195.5

Of course, I've changed subscription-id, vm-name, vm-user and puppet-master-ip and generate a pem file. I'm getting the following error:

"could not initialize global default settings certificate name must be lower case"

Can you help me?