My Ipod Touch 4th generation says iPod is disabled. What do I do to get it active again?

Restore it.

If you are unable then type "unable to restore" into the search bar at the top of this page by Support and read the resulting help article.

Place the iOS device in Recovery Mode and then connect to your computer and restore via iTunes. The iPod will be erased.

iOS: Wrong passcode results in red disabled screen

If recovery mode does not work try DFU mode.

How to put iPod touch / iPhone into DFU mode « Karthik's scribblings