This is a small script for completely removing all references to missing plugins from your 3ds Max scene.
Use with care! and do not save the results under the same file name! The script will replace any missing plugin object with the first usable alternative object of the same class it can find. I cannot give any guarantuees this will not mess up your data, your machine or your live. This could work for versions older than 2008 if you have the free AVGDLX extension installed.
Just open the scene that repors missing plugins and run the script by drag-and-drop or through the MAXScript > Run menu.
Minimal testing so far – if it works or does not work for you, please let me know, thanks!