Chimera identification

Hi,

Sorry for posting a question from QIIME1 on here but I saw that the other forum was not being moderated so turned for help here... hope it's not sacrilege!

I have done open reference OTU picking with SILVA128 and now want to filter the rep_set_aligned.fasta file for chimera using the parallel_identify_chimeric_seqs.py. This the code I am using:

time parallel_identify_chimeric_seqs.py -i ~/2018_02_smb/open_ref_otu2/pynast_aligned_seqs/rep_set_aligned.fasta -a ~/SILVA_128_QIIME_release/rep_set/rep_set_all/97/97_otus.fasta -o ~/2018_02_smb/open_ref_otu2/chimera_seq

This is generating the error I have attached below.

I am very new to using QIIME (doing it for a university project) so apologies for rookie mistakes.

Thanks!