Invalid HTTP Header using .Net TransferUtility

I am getting the following error using the TransferUtilityUploadRequest,

TransferUtility Specified value has invalid HTTP Header characters.Parameter name: name

I beleive the following code is pretty close to the sample code provided by Amazon. Anyone see why I would get this error?

TransferUtilityUploadRequest request = new TransferUtilityUploadRequest();
 request.FilePath = resume.FileInfo.FullName;
 request.BucketName = targetBucket;
 request.Key = key;
 foreach(var property in resume.OtherProperties)
        {
          request.Metadata.Add(property.Key, property.Value);
        }

 var xferUtil = new TransferUtility(client);
 xferUtil.Upload(request);