I am using v. 5.005_02, is it possible that the (??{ }) is not present in this version?
Yup, this is the case. At least I would guess that from your error message - I'm not sure when this feature was introduced but it is quite recent.

-- Hofmator

In reply to Re: Problem with recursive pattern matching by Hofmator
in thread Problem with recursive pattern matching by tshabet

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