.Stepp.plot: no visible global function definition for 'graphics.off'
.Stepp.plot: no visible global function definition for 'dev.new'
.Stepp.plot: no visible global function definition for 'postscript'
.Stepp.plot: no visible global function definition for 'pdf'
.Stepp.plot: no visible global function definition for 'png'
.Stepp.plot: no visible global function definition for 'bmp'
.Stepp.plot: no visible global function definition for 'tiff'
.Stepp.plot: no visible global function definition for 'jpeg'
.Stepp.plot: no visible global function definition for 'dev.list'
.Stepp.plot: no visible global function definition for 'dev.set'
.Stepp.plot: no visible global function definition for 'par'
.Stepp.plot: no visible global function definition for 'points'
.Stepp.plot: no visible global function definition for 'axis'
.Stepp.plot: no visible global function definition for 'mtext'
.Stepp.plot: no visible global function definition for 'legend'
.Stepp.plot: no visible global function definition for 'qnorm'
.Stepp.plot: no visible global function definition for 'lines'
.Stepp.plot: no visible global function definition for 'dev.off'
cuminc.HR: no visible binding for global variable 'na.omit'
cuminc.HR: no visible global function definition for 'pchisq'
kmest: no visible binding for global variable 'na.omit'
ppv2: no visible global function definition for 'var'
ssigma: no visible global function definition for 'var'
estimate,stmodelCOX: no visible global function definition for
  'as.formula'
estimate,stmodelGLM: no visible global function definition for
  'as.formula'
estimate,stmodelGLM: no visible global function definition for
  'gaussian'
estimate,stmodelGLM: no visible global function definition for
  'binomial'
estimate,stmodelGLM: no visible global function definition for
  'poisson'
estimate,stmodelGLM: no visible global function definition for
  'predict'
estimate,stmodelGLM: no visible global function definition for 'coef'
estimate,stmodelGLM: no visible global function definition for 'vcov'
generate,stsubpop: no visible global function definition for 'median'
test,stmodelCI: no visible global function definition for
  'txtProgressBar'
test,stmodelCI: no visible global function definition for
  'setTxtProgressBar'
test,stmodelGLM: no visible global function definition for 'as.formula'
test,stmodelGLM: no visible global function definition for
  'txtProgressBar'
test,stmodelGLM: no visible global function definition for
  'setTxtProgressBar'
test,stmodelGLM: no visible global function definition for 'gaussian'
test,stmodelGLM: no visible global function definition for 'predict'
test,stmodelGLM: no visible global function definition for 'binomial'
test,stmodelGLM: no visible global function definition for 'coef'
test,stmodelGLM: no visible global function definition for 'vcov'
test,stmodelGLM: no visible global function definition for 'poisson'
test,stmodelKM: no visible global function definition for 'as.formula'
test,stmodelKM: no visible global function definition for
  'txtProgressBar'
test,stmodelKM: no visible global function definition for
  'setTxtProgressBar'
Undefined global functions or variables:
  as.formula axis binomial bmp coef dev.list dev.new dev.off dev.set
  gaussian graphics.off jpeg legend lines median mtext na.omit par
  pchisq pdf png points poisson postscript predict qnorm
  setTxtProgressBar tiff txtProgressBar var vcov
Consider adding
  importFrom("grDevices", "bmp", "dev.list", "dev.new", "dev.off",
             "dev.set", "graphics.off", "jpeg", "pdf", "png",
             "postscript", "tiff")
  importFrom("graphics", "axis", "legend", "lines", "mtext", "par",
             "points")
  importFrom("stats", "as.formula", "binomial", "coef", "gaussian",
             "median", "na.omit", "pchisq", "poisson", "predict",
             "qnorm", "var", "vcov")
  importFrom("utils", "setTxtProgressBar", "txtProgressBar")
to your NAMESPACE file.