repair tasks for Keynote 6.1
Try this repair for iWork applications, its sorted out many similar problems, ensure you complete all the tasks and in the order shown:
1 delete all the iWork applications if you have them, not just Keynote by using Appcleaner from Mac Update to do this, its freeware
2 restart the Mac; Apple menu > restart
3 immediately after the start chime, press the shift key until you see the Apple symbol.
let it fully boot up, it will take longer as the OS is repairing the drive
4 when fully booted, go to Applications > Utilities > Disc Utility; click on the boot drive then First Aid tab and click repair disc permissions
5 when complete, restart the Mac normally
6 install Keynote from the Mac App Store
Please report back to let us know how this helped.
I followed all of the steps you suggested and the problem persists. I do believe it is a problem with permissions, since I can create a new Keynote presentation from a template when I use a different account. Repairing the disk, and repairing the permissions did not fix the problem in my main account. Perhaps there is an old file causing problems that needs to be deleted?