Humm... I was using adegenet / ade4 packages and both R and R studio prompted the questions. Sorry, I did so many searches on R help and Adegenet help that I forgot to mention the packages I was using... Juliana -- View this message in context: http://r.789695.n4.nabble.com/error-message-tp3223412p3994158.html Sent from the R help mailing list archive at Nabble.com.