These figures came from the Pew Center on the States study entitled "Inaccurate, Costly, and Inefficient: Evidence that America's Voter Registration System Needs an Upgrade" (2012).  These "glitches" were not removed from the system due to the Obama Department of Justice suspending the execution and enforcement of federal law in relation to the regulations governing elections.

The National Voter Registration Act (NVRA) of 1993, 52 USC is the law we're examining here, specifically Section 8 that is specifically designed to promote honest and fair voting in the elections.  Section 8 is a requirement for the states.  They are to do the following in accordance with the law:

"…conduct a general program that makes a reasonable effort to remove the names of ineligible voters from the official lists of eligible voters."