Consider using the haven package for importing SAS, Stata, and SPSS files; haven stores labels as the label attribute of each variable as does Hmisc; it converts date and time variables automatically and allows one to specify a format catalog along with the primary dataset
See if the readstata13 package has advantages over the foreign package for Stata file import
Consider creating xl.get using the readxl package to read .xls and .xlsx Excel files
In impute.transcan, sense if a variable in data is not a factor whereas it was treated as a factor during aregImpute; it should be converted to factor before the line v[sub] <- ... levels(as.integer...)) is run