The @ sign in your connect string is being interpreted as designating an rman array.

You want a literal @ sign. Which requires … if you wanted to embed a " in a " delimited string you would …?

Ah, this always aggravated me until my habits caught up with Perl. Use a \ before the @ to escape it

              connect catalog aaaaaaaaa/bbbbbbbb\@rman-live
[download]

Update: When faced with a warning or error you're having troubles figuring out `man perldiag` is helpful. The explanations are concise and give examples.