Thread:Project:Support desk/Exception thrown while uploading documents - ezMediawikiLuceneSaveHook failed to return a value/reply (6)

I cannot promise that as I do not know your setup, plus I don't know from what you migrate from. However I'd recommend to grep the source where ezMediawikiLuceneSaveHook is used. I guess you have checked out https://www.mediawiki.org/wiki/Manual:Configuring_file_uploads already?