I tested the file and confirmed it wasn't working - not sure why the sample list isn't showing. I've had similar problems before and have been unable to pinpont the problem - I suggest converting your BIOM file back to a classic OTU table, and then re-converting back to BIOM (maybe some field got changed during the initial generation that is interfering with Phinch). Commands to run are as follows:
biom convert -i original_file.biom -o classic_OTUtable.txt -b --header-key=taxonomy
biom convert -i classic_OTUtable.txt -o new_BIOM_file.biom -m mapping_file.txt --table-type="otu table" --process-obs-metadata=taxonomy
biom add-metadata -i new_BIOM_file.biom -o new_BIOM_file_with_metadata.biom -m mapping_file.txt
Then try to load in Phinch again - Let me know if this works!