How to upload file from external dll vb project

hi sir,

         thanks for ur reply

the version i used for dropbox api 6.25  for one 

for two below code

var dpClinet = new Dropbox.Api.DropboxClient(TokenKey);
try
{
UploadArg uploadArg = new UploadArg(folder, WriteMode.Overwrite.Instance, true);
using (var mem = new MemoryStream(File.ReadAllBytes(fileToUpload)))
{
// var mem = new MemoryStream(File.ReadAllBytes(fileToUpload));
// var updated = await dpClinet.Files.UploadAsync(uploadArg, mem);
//var updated = await dpClinet.Files.UploadAsync(folder, WriteMode.Overwrite.Instance, body: mem);
FileMetadata fileMetadata = await dpClinet.Files.UploadAsync(folder, mode: WriteMode.Overwrite.Instance, autorename: false, body: mem);

}
}
catch(Exception ex)
{
DoNotify(ex.Message);
DoNotify(ex.StackTrace);
}

for three below errors

An error occurred while sending the request.

at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Dropbox.Api.DropboxRequestHandler.<RequestJsonString>d__20.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Dropbox.Api.DropboxRequestHandler.<RequestJsonStringWithRetry>d__18.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Dropbox.Api.DropboxRequestHandler.<Dropbox-Api-Stone-ITransport-SendUploadRequestAsync>d__13`3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
at AmberSoftDBPlugin.AmberSoftDB.<UploadFilesToDropBoxAsync>d__0.MoveNext() in D:\AmberSoftDBPlugin\AmberSoftDBPlugin\AmberSoftDB.cs:line 42