ped<-system.file('extdata/inter.ped',package="GeneGeneInteR")
info <- system.file("extdata/inter.info",package="GeneGeneInteR")

posi <- system.file("extdata/inter.txt",package="GeneGeneInteR")

data <- importFile(file=ped, snps=info, pos=posi, pos.sep="\t")

Before is the code i load the data into R. when i trying to combine these three file. Error RUNS like this:

Error in snpStats::read.pedfile(file = file, ...) : 
  could not create unique subject identifiers
In addition: Warning message:
In snpStats::read.pedfile(file = file, ...) :
  1 loci were multi-allelic --- set to NA

I cant figure out whatis wrong with the file format. Can sb help me?