Download files from Amazon S3 windows command line utility

Question

I am tasked to automate the process of downloading files from Amazon S3. I am quite new this, after searching on the web I found this command line utility for windows s3.exe I run the get command with the below syntax

s3 get xxx-xxx/yyyy_yyy/ D:\ /key:****** /secret:*****

xxx-xxx(bucketname) yyyy_yyy(keyprefix) D:(local path)

When I execute this the only message i see is s3.exe version 2.0 - check for updates at http://s3.codeplex.com and then it takes me back to the folder where I run the command. Pardon me if this too basic a question for this forum but if anyone have used this utility some insights will help me achieve this