Here is the error trace pulled from the image processing log:
Image processing failed. Error message from the server: SsiServerCommunication.SsiClientSessionException: Request failed for command 'GetInputFileDetails' with error code '-1' and error message: 'System.ArgumentNullException: Value cannot be null.
at SsiServerCommonUtils.BlockEncryptor.DecryptAdvanced(Byte[] inputBuffer, String key, String salt)
at SsiServer.ServerLogic.Implementations.BatchFileInputLogic.GetInputFileDetailsImpl(String fileId, Byte[]& fileBuffer, String& fileName, String& processingSettings)
at SsiServer.ServerLogic.Implementations.BatchFileInputLogic.GetInputFileDetails(String fileId, Byte[]& fileBuffer, String& fileName, String& processingSettings)'
at SsiServerCommunication.Clients.SsiTcpClientSession.ValidateRequestResult(BinaryCommand resp)
at SsiServerCommunication.Clients.SsiTcpClientSession.PerformRequest(Stream stream, BinaryCommand request)
at SsiServerCommunication.Clients.SsiTcpClientSession.GetInputFileDetails(String fileId, String& fileName, String& processingSettings)
at SsiImageProcessingClient.ImageProcessingLogic.ImageProcessingWorker.PerformImageProcessing(String fileId)
at SsiImageProcessingClient.ImageProcessingClient.DoWorkImpl(Object sender, DoWorkEventArgs e)