MIght have been helpful to mention how many hops you did and what kind of browser and computer you're using.
But I purposely did about 50 hops, about 10 rated up, 1 rated down, on IE8, Windows XP and had no issues.
If you're having continuous issues, find out if perhaps it's your browser. If you're using FF, try turning off all your addons. If you're using IE 6 or IE 7, try upgrading to IE 8. If you're using IE 8, also try turning off your addons.
If those don't work try switching browsers. Here's a list of good browsers. If you're already using one, pick another and temporarily install it to find out if your situtation gets better: FF2, FF3, IE7, IE8, Chrome, Opera, Safari.
If you're still having issues. Try clearing cache and cookies. You can usually use your browser to clear those, or you can either download CCleaner or Glary Utilities and run them.
If you're still having issues, then it's your computer being weird and you should seek professional help before doing anything drastic (like reinstalling your OS completely....)