If you have some broken recorded game files that you would like to fix, follow these steps:
1) Download mgxFix utility from here (158 KB, created by biegleux)
2) Unpack it somewhere on your disk (eg. "C:\mgxfix-0.2-win32")
3) Go to your AoC SaveGame folder (eg. "C:\Program Files\Microsoft Games\Age of Empires II\SaveGame"), or wherever your corrupted recorded game is, and select all the files you would like to fix
4) Copy those files to mgxFix folder (where you unpacked it, eg. "C:\mgxfix-0.2-win32")
5) Run "mgxfix.bat" in that same folder (double click it) -- now all the files should be successfully fixed
6) Copy (or cut) the files back to your SaveGame folder (eg. "C:\Program Files\Microsoft Games\Age of Empires II\SaveGame")