Hi @jessicalmetcalf! Thanks so much for writing, sorry to hear things aren't going well. It looks like you found a bug 
, related to some of the behind-the-scenes parsing of metadata in QIIME 2. To make a long story short, QIIME 2 currently uses pandas for parsing TSV metadata. It looks like one of your sample IDs is 'NA':
and, pandas likes to interpret that as a special value representing a null/nan type, which is why you are seeing the Non-string Metadata index values detected error! In the meantime, you could change that sample ID somehow to not use the value 'NA' --- it looks like pandas won't do anything if you use the value 'na', for example.
Sorry for the inconvenience, and thanks for reporting this! 
