[R] i keep getting a check data: there are more than 3 classes for f2 error and I am not sure how to fix it i am using onemap

[Kulvinder Gill]

SNP <- read.mapmaker(dir = "~/desktop", "1674_SNP.raw”)

--please do not edit the information below--

R Version:
platform = x86_64-apple-darwin15.6.0
arch = x86_64
os = darwin15.6.0
system = x86_64, darwin15.6.0
status = 
major = 3
minor = 4.1
year = 2017
month = 06
day = 30
svn rev = 72865
language = R
version.string = R version 3.4.1 (2017-06-30)
nickname = Single Candle

GUI:
R-GUI 1.70 (7375)

Locale:
en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

Search Path:
.GlobalEnv, tools:RGUI, package:stats, package:graphics,
package:grDevices, package:utils, package:datasets, package:methods,
Autoloads, package:base