extractLMS: no visible global function definition for ‘approx’
wp.twin : coplot2: no visible binding for global variable ‘points’
wp.twin : coplot2: no visible global function definition for ‘par’
wp.twin : coplot2: no visible global function definition for ‘gray’
wp.twin : coplot2: no visible global function definition for
  ‘co.intervals’
wp.twin : coplot2: no visible global function definition for ‘plot.new’
wp.twin : coplot2 : do.panel : Paxis: no visible global function
  definition for ‘axis’
wp.twin : coplot2 : do.panel : Paxis: no visible global function
  definition for ‘Axis’
wp.twin : coplot2 : do.panel: no visible global function definition for
  ‘par’
wp.twin : coplot2 : do.panel: no visible global function definition for
  ‘plot.new’
wp.twin : coplot2 : do.panel: no visible global function definition for
  ‘plot.window’
wp.twin : coplot2 : do.panel: no visible global function definition for
  ‘grid’
wp.twin : coplot2 : do.panel: no visible global function definition for
  ‘box’
wp.twin : coplot2: no visible global function definition for ‘mtext’
wp.twin : coplot2: no visible global function definition for
  ‘plot.window’
wp.twin : coplot2: no visible global function definition for ‘rect’
wp.twin : coplot2: no visible global function definition for ‘text’
wp.twin : coplot2: no visible global function definition for ‘Axis’
wp.twin : coplot2: no visible global function definition for ‘axis’
wp.twin : coplot2: no visible global function definition for ‘box’
wp.twin : wp2: no visible global function definition for ‘fitted’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘par’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘qqnorm’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘grid’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘points’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘abline’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘pnorm’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘dnorm’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘qnorm’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘lines’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘lm’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘spline’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘fitted’
wp.twin : wp2 : panel.fun: no visible global function definition for
  ‘coef’
wp.twin : wp2: no visible global function definition for ‘qqnorm’
wp.twin : wp2: no visible global function definition for ‘resid’
wp.twin : wp2: no visible global function definition for ‘pnorm’
wp.twin : wp2: no visible global function definition for ‘dnorm’
wp.twin : wp2: no visible global function definition for ‘qnorm’
wp.twin : wp2: no visible global function definition for ‘plot’
wp.twin : wp2: no visible global function definition for ‘grid’
wp.twin : wp2: no visible global function definition for ‘abline’
wp.twin : wp2: no visible global function definition for ‘lines’
wp.twin : wp2: no visible global function definition for ‘lm’
wp.twin : wp2: no visible global function definition for ‘spline’
wp.twin : wp2: no visible global function definition for ‘co.intervals’
wp.twin : wp2: no visible global function definition for ‘mtext’
y2z : y2z.grp: no visible global function definition for ‘approx’
y2z : y2z.grp: no visible global function definition for ‘qnorm’
z2y : z2y.grp: no visible global function definition for ‘approx’
z2y : z2y.grp: no visible global function definition for ‘pnorm’
Undefined global functions or variables:
  Axis abline approx axis box co.intervals coef dnorm fitted gray grid
  lines lm mtext par plot plot.new plot.window pnorm points qnorm
  qqnorm rect resid spline text
Consider adding
  importFrom("grDevices", "gray")
  importFrom("graphics", "Axis", "abline", "axis", "box", "co.intervals",
             "grid", "lines", "mtext", "par", "plot", "plot.new",
             "plot.window", "points", "rect", "text")
  importFrom("stats", "approx", "coef", "dnorm", "fitted", "lm", "pnorm",
             "qnorm", "qqnorm", "resid", "spline")
to your NAMESPACE file.