why group file is necessary

Hi Everyone,
I am trying to build OTUs , this command is giving me problem:
mothur > make.shared(list=final.an.list, label=0.03)
“You need to provide a groupfile or countfile if you are going to use the list format.”
I never made any group file since starting (when I aligned my reads).
Is it necessary to make group file as I am dealing with only one set of data.

Any kind of help is appreciated!!!

make.shared makes a table indicating the number of reads per group per OTU. If you only have one sample/group then you don’t need to run make.shared. But then again, if you only have one sample, what can you compare it to?

Thanks Pat,
So, I don’t have to run make.shared command.
I have a set of reads which I got by sequencing the ice sample from glacier. I had just one sample and these reads are coming from that only. As I am doing it very first time( new in the field of bioinformatics) I would like to know if there is a need for a sample to compare.

Thanks for all the help!!!