After entering password, you get error:

niutil: can't get property users in directory /groups/uucp: No such property

And the current user doesn't get added to the uucp group. They get a permission denied error
when trying to access the serial port from a sketch. I've been working around this with:

sudo chmod 777 /var/spool/uucp/

Both machines were running Tiger, though I don't know if that's relevant.

yep, i think it's a tiger issue.. i don't have a tiger machine yet so i haven't run into it, but
we've been getting more reports of things like this coinciding with the release of tiger.

now using the arduino rxtx jnilib, so we shouldn't have any more group
troubles.