Having the same problems. WTB a working WoWAceUpdater!
I too started having problems with the latest version of the WAU.
This may fix some problems:
For those who still have not uninstalled and reinstalled:
1. Go to the Control panel > Add/remove programs
2. Select the WowAceUpdater and click the Change/Remove button
3. You should see an option to revert back to the previous version (188.8.131.528) like mine did or to remove the program entirely.
4. Select previous version and wait for it to sort itself out.
After this, the WAU worked fine for me.
For anyone who did remove the program, I suggest getting WAU 184.108.40.2068, as I know it still works.