Amazon EC2 to S3 transfer

Question

I wanted to backup my EC2 instance to S3. I downloaded EC2 tools from: http://developer.amazonwebservices.com/connect/entry.jspa?externalID=351.

I set up environment variables to:

EC2_HOME=<EC2 tools directory>
EC2_PRIVATE_KEY=<path to private key generated after I created new X.509 certificate>
EC2_CERT=<path to certificate I created in X.509 Certificate tab>
JAVA_HOME=<path to java jre>

When I run command:

ec2-bundle-instance -b bucket_name -p bucket_prefix -o access_key i-23084b49 -w secret_access_key

I keep getting the message:

Client.InvalidInstanceType: Instance i-23084b49 does not support bundling.

Do you have any idea why?

What do you recommend as easiest way of backing up EC2 to S3?

Thanks.