I've been to many blogs and read posts regarding this problem and i once and for all want to sort this out, i'm too lazy to keep typing the same thing everywhere. So here's the simple solution to a common problem.
Step 1:-Stop the torrent if it does not progress for a long period of time
Step 2:-Right-click on the torrent and select the option for "Manual Hash Check". At this point, the torrent will turn a yellow circle.
Step 3:-After completing 'Step 2', the torrent will have a grey circle and will show the 99.xx%.
Step 4:-Start the download again.
(Optional) Right-click the torrent again after completing 'Step 4' and select the option "Manual Connect".
Hope this has solved the problem that many people have had. :)
Cheers & Glad to be of help,
RD90