RVM shows me my bash is out of date

RVM shows me my bash is out of date

ERROR ENCOUNTERED:
Ruby Version Manager (RVM)
[wreilly@gmc-mac] 
~ $ rvm package install readline
/Users/wreilly/.rvm/scripts/package: line 181: conditional binary operator expected
/Users/wreilly/.rvm/scripts/package: line 181: syntax error near `=~'
/Users/wreilly/.rvm/scripts/package: line 181: `  if [[ " readline iconv curl openssl zlib autoconf ncurses pkgconfig gettext glib mono llvm libxml2 " =~ "$library" ]] ; then'

OLD BASH THE REASON (?)
<a href="http://gist.github.com/301384>http://gist.github.com/301384</a>
"...had old version on bash installed (on Mac OSX 10.4),..."

This MacBook Pro = 10.4.11
$ bash --version
bash --version
GNU bash, version 2.05b.0(1)-release (powerpc-apple-darwin8.0)
Copyright (C) 2002 Free Software Foundation, Inc.
$ echo $BASH_VERSION  
echo $BASH_VERSION 
2.05b.0(1)-release


UPGRADE BASH INFO:

Not yet tried either of these.

(1)
http://archive.hmug.org/BSD/Applications/Shells/bash/
Latest version (that I see) for OS X 4:
http://archive.hmug.org/BSD/Applications/Shells/bash/README.bash-4.0-1p35-osx4-x86.html
Few instructions: (?)
$mv bash-4.0 /tmp
$cd /tmp/bash-4.0
$sudo make install 
Password:********
That's it!

(2)
Fuller instructions (doesn't say which OS X; I'm guessing later than 4)
http://concisionandconcinnity.blogspot.com/2009/03/upgrade-bash-to-40-in-mac-os-x.html