Barbara, while I can not make a ringing endorsement of the methods suggested by Customer Support, their intention is to clear up database corruption, without the user changing the data directly. Not by uploading to other software but by uploading the exported ged/tree back into FTM.
It does appear to work using the ged method. I exported a ged (formatted for FTM2012) from FTM of my 44,000 people tree. Then I reimported the ged back into FTM. The resulting tree as then able to uploaded and linked as a new 44.000 person tree in Ancestry, with no modifications. This is something I have been totally unable to do with the original tree since my database problem began.
However of course my 30,000 pieces of media were not part of the process, so I have no cause to really celebrate. But I do have a 44,000 person data only tree on Ancestry now. Before the export/import I was only able to create 0 person trees on Ancestry from the corrupted FTM2012 database.
But in the end we would all wish for a tool that identifies the point of error/corruption in the database. The methods suggested may fix the corruption, but leave no idea where the corruption was or what it was. And no idea what piece of data may have been lost during the shakeout using these methods.