problems connecting to itunes

When i try to connect my touch to my computers it says device driver not found and to contact manufacturer for a driver or other software. What does that mean and what do i have to do? Sometimes it will connect and then just disconnect and say it couldn't be found. i thought maybe it was just the usb port on the computer but it does it on both of our computers. I had the same problem with my other ipod touch. used to say it couldn't be found on my computer so i had to use my husbands to connect to itunes. Sometimes i wonder if this whole itunes thing is really worth it i love my ipod touch and plan on getting a ipad but this itunes on my computer really has me wondering.