Yes I understand, your problem, but to provide answer for your question I need to know the following things:
[i]What was the firmware on your device before you tried to update?
What is the firmware version what you try to upload to the device?
As the current firmware release has no USB updater I assume you try to apply some older firmware right? Is there any special reason for this?[/i]
Please try to use the current firmware release with network update method. To discover your uTrack24 IP address (if you have no access to check the IP address on the screen) you can use the application called Fing. Install that application on your Android or Apple phone/tablet make sure the uTrack24 connected to the same network like your phone/tablet then start the application to discover your uTrack24 on the network.