error when connecting to amazon s3

Hi, I created an user on aws, set up the "AmazonS3FullAccess" policy and generated the access keys.

But I get an error on wordpress when trying to choose the bucket or test connection.

Unknown: errno:2 curl_setopt() expects parameter 2 to be long, string given /mywebsite.com/wp-content/plugins/snapshot/lib/destinations/aws/AWSSDKforPHP/lib/requestcore/requestcore.class.php on line 621

Here´s a screenshot: http://www.awesomescreenshot.com/image/280516/d7b40fbbafd44d74200d5cc9f11ec90d

Am I doing something wrong?