Apps :: Problem to use USB-to-Serial device

Hi,
    Anybody to help me to solve the problem? When I key in the following command:
cat text.txt > /dev/ttyUSB0
The follwing error message show on the monitor:
"modprobe: can't locate module char-major-188"
It showed that it can't find the USB-to-serial driver. How can I solve the problem? Anybody gives me a suggestion.