Help needed! Error in setwd(newdir) : cannot change working directory

Hi, 
 
I am sorry about the format it showed up. I do not know what happened as now it looks worse even on my own machine. I do not know what to do, I just add "\n" to the end of each line and hope it will come out OK this time. The packages A, B, C are not the real package names.  Basically I have  scriptA.R that works from inside a directory with my data (/home/sean/Rtest/Data01). Now I want to modify the script to make it run from the upper directory (/home/sean/Rtest) because I have many data directories under /Rtest, such as /home/sean/Rtest/Data01, /home/sean/Rtest/Data02, /home/sean/Rtest/Data03,..... I want to modify my script so that it will run from /Rtest, and with the data directory name as arg passed to my R script. My point is that when I put the scriptA.R in data directory such as Data01, it works. Here are my scriptB.R script: 
 
######################scriptA.R######################################### 
 
# load the necessary libraries 
library("A");  # A fake package name 
library("B");  # B fake package name 
library("C");  # C fake package name 
........    #data processing 
........    #data processing 
........    #data processing 
# unload the libraries 
detach("package:A");   
detach("package:B"); 
detach("package:C"); 
q(); 
####################################################################### 

But, when I tried to modify scriptA.R to scriptB.R to run it from the directory just above Data directories, I got the error message. 

###########################scriptB.R#######################################

# retrieve args 
args <- commandArgs(TRUE); 
# store the current directory 
initial.dir <- getwd(); 
newdir <- paste(initial.dir,args,sep="/"); 
outfilename <- paste(args,"out",sep="."); 
# change to the new directory 
setwd(newdir); 

# load the necessary libraries 
library("A");  # A fake package name 
library("B");  # B fake package name 
library("C");  # C fake package name 

# set the output file 
sink(outfilename); 
........    #data processing 
........    #data processing 
........    #data processing 
# close the output file 
sink(); 
# unload the libraries 
detach("package:A");  # 
detach("package:B"); 
detach("package:C"); 
# change back to the original directory 
setwd(initial.dir); 

################################################################## 

I run the scriptB.R by 

sean at I7-3930K:~/Rtest$ R --slave --args Data01 < scriptB.R 

I got the error message: 

sean at I7-3930K:~/Rtest$ R --slave --args Data01 < scriptB.R 
Attempting to load the environment ?package:R.utils? 
Loading required package: R.methodsS3 
R.methodsS3 v1.2.1 (2010-09-18) successfully loaded. See ?R.methodsS3 for help. 
Loading required package: utils 
R.oo v1.8.3 (2011-11-01) successfully loaded. See ?R.oo for help. 

Attaching package: ?R.oo? 

The following object(s) are masked from ?package:R.methodsS3?: 

   throw.default 

The following object(s) are masked from ?package:methods?: 

   getClass, getClasses, getMethods 

The following object(s) are masked from ?package:base?: 

  attach, detach, environment, gc, load, save 

R.utils v1.9.11 (2012-01-17) successfully loaded. See ?R.utils for help. 

Attaching package: ?R.utils? 

The following object(s) are masked from ?package:utils?: 

    timestamp 

The following object(s) are masked from ?package:base?: 

    cat, commandArgs, getOption, inherits, isOpen, lapply, parse, 
    remove, warnings 

[1] "/home/sean/Rtest" 
[1] "/home/sean/Rtest/NA"       "/home/sean/Rtest/TRUE"     
[3] "/home/sean/Rtest/Data01" 
[1] "NA.out"       "TRUE.out"     "Data01.out" 
Error in setwd(newdir) : cannot change working directory 
Execution halted