updated install of rvm 1.6.20 failed on reboot

rvm-1.6.20-reboot-error

from root:
# rvm get latest
...
# rvm --version
rvm 1.6.20 by Wayne E. Seguin (wayneeseguin@gmail.com) [https://rvm.beginrescueend.com/]

$ type rvm | head -1
rvm is a function

reboot - after login instead of standard gnu screen
error message - refers to /usr/local/rvm/scripts/rvm line 57

I rebooted in linux single user mode, commented out line 57:
from
true "${rvm_prefix/rvm/scripts}" # Fix rvm_prefix changes, older installs.
to
#  true "${rvm_prefix/rvm/scripts}" # Fix rvm_prefix changes, older installs.

rebooted again
-problem solved