In case you got a message that Warcraft 3 might be unstable or you encountered any other problems when using the current game version just use the intern recovery function.
Start ReplayKit.exe. If it is installed properly and a backup exists, it asks you for a recovery! Just click 'Yes' and you are done.
(This is only working for release < 1.28)
Drag ReplayKitBackup.mpq and drop it on ReplayKit.exe. Now the recovery should start!