what to do

The first time I came across DMOZ I submitted my url after glancing briefly at their submission guidelines, and after hearing nothing for a few weeks, I re-submitted. After a month or so without hearing anything again I submitted it once more. Then I read more deeply the submission guidlines and realised that they said on no account to keep re-submitting the same url. Does this mean I won't ever get listed because I inadvertenlty, albeit foolishy broke their guidelines. Or should I wait six months or so and re-submit.

If you submitted to the same category each time, and if the site hadn't yet been reviewed each one overwrote the old ones.

It will not harm things, unless the site had already been reviewed and rejected, in which case the repeated submission is spam.

If it was to multiple categories then it begins to look less innocent, but again, an editor will delete all but one submission and leave just one for later review.

Whatever you do from now on, don't submit again.

>Does this mean I won't ever get listed because I inadvertenlty, albeit foolishy broke their guidelines.

No. The death penalty is reserved for serious, persistent spammers. What you describe is way down in the 'noise' level.

And yes, a resubmittal 'much later' (I'd say about a year) would not be unreasonable.