ITunes Errors/31xx

Error 3123
Something dealing with movie rentals.

Error 3191
QuickTime may be corrupted. You must reinstall it before iTunes will work. Windows users, also try turning off Compatibility Mode for QuickTime
 * 1) Right-click on   (  for 64-bit Windows) and choose Properties from the shortcut menu
 * 2) In the Properties window, click on the Compatibility tab. Deselect the checkbox labeled "Run this program in compatibility mode for"
 * 3) Select "Windows XP"
 * 4) Click Apply
 * 5) Close the Properties window