Update...
after some troubleshooting i've found logging as Domain User when trying to "start tutorials" it tries to write into \network area\network\user\ which is a redirection to my documents and hence getting failed. (even though its user's personal area and user have full permissions there)
if create a local standard user or launch the rstudio as admin user then it work just fine.
i could not find anywhere in the application where can change/edit the path to go to my documents as c:\users\user\documents rather then going to \network area\network\user\
will really appreciate if someone can shed a light.
Thank 