How to give path to save file in amazons3?

I am using web api. I want to store file which is stored in filepath. This code works well in my local pc. But when i deployed this code in Server. It is not working. Is there any way to save file from other PCs as well???

string tempPath = Path.Combine(strPath + AttachmentFileName);
                                    string filePath = Path.Combine(tempPath);
                                    string S3_KEY = key;
                                    string S3BucketName = Convert.ToString(ConfigurationManager.AppSettings["BucketName"]);
                                    FileStream stream = new FileStream(filePath, FileMode.Open);


                            PutObjectRequest objReq = new PutObjectRequest
                                            {

                                                Key = AttachmentFileName,
                                                InputStream = stream,
                                                BucketName = S3BucketName + "/" + S3_KEY,
                                                CannedACL = S3CannedACL.Private,
                                                Timeout = 3600000

                                            };

                            PutObjectResponse response = s3Client.PutObject(objReq);


                            objMessage.Attachments.Add(new Attachment(AttachmentFileName));
                            //stream.Flush();
                            //stream.Dispose();
                            response.Dispose();