I am trying to follow the MiSeq_SOP for Mothur (from the Mothur wiki page). When I run make.contigs() I get multiple error messages saying e.g. 'Could not open 7650.num temp'.

I cannot find any information about this error code, so I would most grateful for any suggestions on what this error means, what is causing it and how to resolve it. This is the first 10 lines of the output:

mothur > make.contigs(file=stability.files,processors=32)

Using 32 processors. Processing file pair /mnt/raid10/Pauls/MiSeq_SOP/F3D0_S188_L001_R1_001.fastq - /mnt/raid10/Pauls/MiSeq_SOP/F3D0_S188_L001_R2_001.fastq (files 1 of 20)
Making contigs... 243 '[ERROR]: Could not open 7650.num.temp' 244 243 '[ERROR]: Could not open 7640.num.temp' 244 '[ERROR]: Could not open 7643.num.temp' '[ERROR]: Could not open 7639.num.temp' 244