I guess the first thing is to find out if Linux can see this Toshiba USB DVB-T device that you have and then take alook and see if Linux is actually doing anything with it.
The first thing is perhaps issuing the following command in a Terminal window:
What that command should do is list the usb devices that are currently connected to your system. The output looks something like this:
Bus 001 Device 002: ID 0781:7108 SanDisk Corp.
Bus 001 Device 001: ID 0000:0000
You can see from my example, I have a SanDisk product connected, a SanDisk thumbdrive. So in your case, I would imagine you should at least see a Toshiba product connected.
If you can see the Toshiba DVB-T product in the list, then the next thing to is take a look and see what happens in the background, what does your system do with this device. I like to issue the following command in a Terminal window which tells me all sorts of stuff.
This will output a long list of things about all of the devices on your system, you should be able to spot something in this list that refers to the Toshiba product, especially if the product was connected during boot up I guess.
You can also post the results here as it will make it easier for others to diagnose or provide advice on the next steps.