Non-standard characters in Ascii-Files

Dear R-list

In R 2.1.1 under Win XP on a P4 with 2GB Ram when typing

temp<-matrix(c(1:16000000),4000,4000)
write(file="temp.txt", temp)
scan("temp.txt")

I receive:
Error in scan("temp.txt") : scan() expected 'a real', received '414851'

The motivation for evoquing this meassage is that I am getting the same
meassage with exported Ascii-Files from the GIS. The files contain very
few, randomly scattered non-standard Ascii-characters. This seems to be
a local problem on my machine but I do not have a clue on the reason
(OS, Memory, HD?) nor who to ask. 
So, my apologies for misusing this list and many thanks for any
suggestion.

Kind regards
Manuel