cannot build on RHEL 6

I copied the source directories to a RHEL 6 machine and ran configure. I got
a vague error about a bad interpreter. 

I then ran bash --debugger configure. I got a syntax error near line 19
(elif). I tried various combination and finally deleted the elif code since
I knew I didn't have zsh. I then got an error at the subsequent 'for as_var
in LANG LANGUAGE...'... syntax error near unexpected token LANG.

If I run bash --version it shows 4.1.2.

Any ideas?