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Perhaps you could try making a copy of the file, and delete one item after another until you find the offending component? Having opened the file in Notepad++, I see that elements in the schematic are defined by 'pin', 'symbol', 'connector' and 'junction'. Start with the component you think is causing the trouble. Make sure though to delete the entire component from bracket to bracket, no more, no less, otherwise it certainly won't work!
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This worked for me - I would suggest looking in the .BDF file for quote marks without any content. I mean like this "" as this is so easy to happen in schematic as the CTRL C does not work and deletes the net name!