Jeong,
Try the following:
1) make sure you have the most recent version of AFNI:
@update.afni.binaries -d
2) have all the required R packages installed:
rPkgsInstall -pkgs ALL
3) remove option "-wsE2 " from your 3dMVM script
4) run the following command if you still have trouble running the script:
afni_system_check.py -check_all
Gang