plot SVM

I use svm , then I want to do like this
But give me this error. Does anyone know how to solve these?

Aimin

 > plot(m.svm,p5.new,As~Cur)
Error in scale(newdata[, object$scaled, drop = FALSE], center = 
object$x.scale$"scaled:center",  :
         (subscript) logical subscript too long