boot.relimp.default.intern: no visible global function definition for
  'lm'
boot.relimp.formula: no visible global function definition for
  'naprint'
boot.relimp.formula: no visible global function definition for
  'model.response'
boot.relimp.formula: no visible global function definition for 'lm'
boot.relimp.lm: no visible global function definition for
  'model.matrix'
calc.relimp.default.intern: no visible global function definition for
  'complete.cases'
calc.relimp.default.intern: no visible global function definition for
  'model.matrix'
calc.relimp.default.intern: no visible global function definition for
  'lm'
calc.relimp.default.intern: no visible global function definition for
  'cov.wt'
calc.relimp.formula: no visible global function definition for
  'naprint'
calc.relimp.formula: no visible global function definition for
  'model.response'
calc.relimp.formula: no visible global function definition for 'lm'
calc.relimp.lm: no visible global function definition for
  'model.matrix'
calcrelimp.forboot: no visible global function definition for 'cov.wt'
calcrelimp.forboot.fixed: no visible global function definition for
  'cov'
calcrelimp.forsurvey: no visible global function definition for
  'cov.wt'
carcalc: no visible global function definition for 'cov2cor'
genizicalc: no visible global function definition for 'cov2cor'
plot.relimplm: no visible global function definition for 'par'
plot.relimplm: no visible global function definition for 'barplot'
plot.relimplm: no visible global function definition for 'title'
plot.relimplm: no visible global function definition for 'mtext'
plot.relimplmbooteval: no visible global function definition for 'par'
plot.relimplmbooteval: no visible global function definition for
  'barplot'
plot.relimplmbooteval: no visible global function definition for
  'segments'
plot.relimplmbooteval: no visible global function definition for
  'title'
plot.relimplmbooteval: no visible global function definition for
  'mtext'
Undefined global functions or variables:
  barplot complete.cases cov cov.wt cov2cor lm model.matrix
  model.response mtext naprint par segments title
Consider adding
  importFrom("graphics", "barplot", "mtext", "par", "segments", "title")
  importFrom("stats", "complete.cases", "cov", "cov.wt", "cov2cor", "lm",
             "model.matrix", "model.response", "naprint")
to your NAMESPACE file.