When changing level addresses on GL20 or AC10 make sure to specify all the level addresses, not just the ones that might have changed.
When you create the file for uploading, make sure to have the first level first, the second level next and so on until all levels are rebuilt. If you try to change an address to one which has upper levels that did not exist in the old system, you will get errors.
Just like building the level addresses, you start with level 1, add a level 2 to an existing level 1 and so on. Same thing when you rebuild the addresses – make sure to rebuild level by level.