Fail to run dataframe.R examples

I get an error=2 running spark-submit examples/src/main/r/dataframe.R
the script is working with Rstudio but i've changed the library(SparkR) line  with this one

library(SparkR, lib.loc = c(file.path(Sys.getenv("SPARK_HOME"), "R", "lib")))

i am at the top root directory of spark installation and the path variable for /bin is specified in the environment so spark-submit is found.  On system window 7 Ultimate 64bits

read "main" java.io.IOException: Cannot run program "Rscript": CreateProcess error=2, The system cannot find the file specified

I think the issue is known for a long but i don't find any post.
Thanks for answer.