Portfolio tag's not getting pulled?

I am new to WP but have been programing for years…

i am using the portfolio section and the tag filters don’t seem to be working.

this isn’t mine but its exactly the same:
here

i can add the tags & they show up as buttons, but when doing array dumps on protfolio.php i think i have been able to narrow down the problem to this line:
$wp_query->query_vars['portfolio_category']

that always spits back empty & i think that’s the reason the tag filtering is not working. Again i am no pro with wp but as far as i can trace back that seems to be the problem.

any ideas? thanks,
-aPeg