[R] Errror in running R2.7.1 version to R2.6.2 version

[Lazarus Mramba]

Dear all,
I get an error shown below when i run the command "use" found in
package epicalc on R2.7.1 and R2.7.0 but dont get the error when i run
it on R 2.6.2

What is likely to be the problem?

library(epicalc)
Loading required package: foreign
Loading required package: survival
Loading required package: splines


use("malvac.dta")
Error in fromchar(x) : 
  character string is not in a standard unambiguous format


use("maltreat.dta")
Error in fromchar(x) : 
  character string is not in a standard unambiguous format

I have attached the datasets (Stata datasets) herein.




Kind regards,
Lazarus Mramba
Junior Statistician
P.O Box 986, 80108,
Kilifi, Kenya
Mobile No. +254721292370
Tel: +254 41 522063
Tel: +254 41 522390
(office extension : 419)