Wireshark showing contant/continuous DNS lookups on 10.6.4

I read elsewhere that someone else having trouble with wifi after upgrading to 10.6.4 recommended deleting the Airport entry on the Network page in System Preferences and then adding it back. I've no idea what this does, but what do you know, the continuous DNS lookups have stopped and all of a sudden my wifi has become lightning fast!

I'm honestly not sure if this started after upgrading to 10.6.4, but the only other network related change I may have made in the past few weeks was to use Hotspot Shield which I seem to remember screwed up my dns servers after I uninstalled it (I ended up with some additional dns servers showing up in my list in the Network Settings instead of my ISPs servers). Anyway, looks like problem solved.

So it appears that this is a temporary fix. Every time I reboot the issue comes back. Everything else on my wifi grinds to a halt as soon as I boot my mac. If I disable Airport and then re-enable it this seems to stop the constant DNS lookups, but only until I reboot then the issue comes back.

Is anyone else seeing this or do you have any idea what is causing this or how I can permanently fix this? This is incredibly annoying.

I did a 'dscacheutil -flushcache' - the funny thing is this just highlights the issue even more. All the dns lookups that seem to be coming from Safari doing its new DNS pre-lookups stop, and all I get is tons of:

Standard Query SOA local

followed by the response:

Standard query response, no such name.

Any other ideas? It's getting to the point where I don't want to turn on my Mac if anyone else in the house is also on the Wifi, because as soon as I turn on my Mac their internet response time turns into dial-up speeds, and worse, they know it's my Mac (and yes, this is the only Mac in the house, so it's not painting a good image for Macs right now...)

V. frustrated!