I have converted a vcf file to the plink format

plink --file Variants --allow-no-sex
plink --file Variants --recodeA --out VariantsA --allow-no-sex
plink --file Variants --recode12 --out Variants12 --allow-no-sex

and tried to read these files into R using:

plink.data <- read.PLINK(file="VariantsA.raw", parallel=FALSE)

but get the following error

Error in checkAtAssignment("SNPbin", "ploidy", "numeric") : 
  assignment of an object of class "numeric" is not valid for @'ploidy' in an object of class "SNPbin"; is(value, "integer") is not TRUE

Any help on what might be causing this would be much appreciated. I have looked through the vcf, ped, and raw file but can't seem to find anything wrong