Solved - It was my router, that had some issues routing this traffic in between Wired & WiFi connections. When I switched both to WiFi, it worked right away.
Problem - Can't access Mac Mini's shared folders and screen via the Macbook
Problem Machine - Mac Mini running 10.5.8
Test Machine - MacBook running 10.6.7
This is an odd support request for me. I have never ever had this issue with my macs. Currently running Lion, Snow Leopard, Leopard on MBPs, MBs, Minis & a Hackintosh box as well. Everything has worked flawlessly forever.
However, I suddenly had to reformat a hard disk on my mac mini and I decided to try out Leopard (for reasons I forget & most likely will upgrade to SL tomorrow). Now I can't access Remote Desktop or share files with that box via any of my devices. I have tried all the usual stuff - Connect As, Change permissions -> no permissions, checked net connections, wifi -> wired, cleared nvram blah blah. Everything anybody has mentioned I have done.
At this point, I am ready to move to SL but just for the sake of knowing what could ever go wrong, I wanted to figure this out. Any help is appreciated.
Update: So as it turns out, I can use Screens (iPad app for VNC) to access my mini's desktop. But I can't seem to get it going on my SL machines yet. I tested my SL macbook to remote control other boxes & it works flawlessly.