regex doesn't recognize {0} as expected

From: jkharris_at_[hidden]
Date: 2001-09-24 14:00:55

I want to use {0} as a "doesn't match" qualifier, so that

    "abcdef" does not match "^(?:abc){0}"

but, alas, it *does* match.  In fact, it doesn't matter whether I supply {0} or {1} in the above regex.

How do I express a negative assertion on a multi-character subexpression?

thanks to whomever responds,

john harris