Good afternoon,
Thanks for posting your full script. I noticed this section:-i $PWD/16S_HS,S,MR,R_chimeras_filtered.fna
I see commas (,) inside of your file name. Qiime uses commas to separate different inputs, so having commas inside your file name confuses qiime.
If you rename your file from -i 16S_HS,S,MR,R_chimeras_filtered.fna to -i $PWD/16S_HS_S_MR_R_chimeras_filtered.fna, this should work better.
Let me know if this works for you,
Colin