Problems with pre.cluster / diff=5

Dear all,
after Illumina sequencing of 16S rRNA regions V345 (500 bp) I was trying to follow to the protocol of schloss et al. In chapter pre.cluster it is explained that for each 100 bp a difference of 1 should be allowed. First I run the protocol with diff=2 - everything was working out. Then I realized that for my dataset, I have to allow diff=5. but for this command I got a error message - see below:
problem is, that I only got the unique sequences and I need the label 0.03.

mothur > pre.cluster(fasta=merged.5.trim.trim.contigs.trim.unique.good.filter.unique.fasta, name=merged.5.trim.trim.contigs.trim.unique.good.filter.names, group=mergegroupsgood, diffs=5)

Output File Names:
mothur > classify.otu(,,, label=0.01-0.03-0.05)

reftaxonomy is not required, but if given will keep the rankIDs in the summary file static.
Your file does not include the label 0.01. I will use unique.
Your file does not include the label 0.03. I will use unique.
Your file does not include the label 0.05. I will use unique.
unique 91214

Output File Names:

mothur > make.shared(,, label=0.01-0.03-0.05)


Output File Names:

Do anybody has a clue what could be the problem?

Many thanks in advance!

When you run summary.seqs on the data after pre.cluster how long are the fragments?

Also, you’ll want to see this if you are sequencing the V3-V5 region: