Here's my solution. It doesn't run your exact test program, because it uses $_. It's 74 chars. Oh, I also obfuscated it.

sub fib {
$_=pop;$==$}=0;{s&^(.)\1{$=}(?!\1)&&&&($==($}+=++$=)-$=,redo)}''eq$_&&
+$=>1
}
[download]

_____________________________________________________
Jeff japhy Pinyan: Perl, regex, and perl hacker.
s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;