Please check the following:
 

• Did you turn on the P-touch after it was connected to the computer?
  If you do not turn it on, the computer does not recognize that the P-touch was connected.
• Depending on the model of the USB Hub, the P-touch may not be correctly detected.
  Connect the P-touch directly to the USB connector of the computer.

If you still get the same problem, download the latest printer driver from the [Downloads] page and try to install it again.