Error importing Casava 1.8 demultiplex format

Hey all,
I am running qiime-2018.11 version and trying to import casava 1.8 demultiplex format. I am re-running the code since I needed to change a couple of labels. I did not have problems with when I run my code the first time (see below):

CarmenP$ qiime tools import

–input-format CasavaOneEightSingleLanePerSampleDirFmt

–input-path fastq/

–output-path SoyExe_demux.qza

–type “SampleData [PairedEndSequencesWithQuality]”

However, now that I want to re-import the data with a couple of changes (I changed the labels of some files from 15 to 15B), I used the following code (the one available in qiime2 docs):
qiime tools import --input-path fastq --input-format CasavaOneEightSingleLanePerSampleDirFmt --output-path demux.qza --type ‘SampleData[PairedEndSequencesWithQuality]’

And I got the following error message:
There was a problem importing fastq:

** fastq is not a(n) CasavaOneEightSingleLanePerSampleDirFmt:**

** Duplicate samples in forward reads: {‘16’}**

This is an example of one of my files names:

Anyone experienced something similar?

Hey there @cortegas!

Can you run ls in the directory that has your files in it? It looks like you have a sample (16) listed more than once in the forward reads.