Macbook Pro / PowerMac G5 Networking problem

I have a Dual 1.8 GHz PowerMac G5. I also have a MacBook Pro 1.83 GHz (Core Duo).

PROBLEM:
Cannot connect from G5 to MacBook. I CAN connect the other way (Macbook to G5). From the G5, when I go to Network (Shift-CMD-K from finder) I see the Macbook Pro but when I try to connect I get the "Connection Failed - Server may not exist blah blah blah" message. From what I can see, Appleshare and network settings are correct (Appleshare is on) on both machines.

Connecting from Macbook Pro to G5 works like it's supposed to. Go to network, see G5, click connect, enter password and voila.

Any idea what's up?

MBP is connected to network via Airport. G5 is through Ethernet.

(FYI - I connected the MBP via ethernet also but had the same result)

Thanks!