I have a similar problem.
I have 2 computers (and other ethernet addressable devices (printer etc) upstairs connected into a gigabit switch (d-link DG-2205) - computer A is an old 2002 G4 without wifi, computer B is a 2010 Mac mini wired into the switch. Downstairs, I have Computer C - a 2012 Mac mini connected to the fios router via wifi and there is a 1080p Apple TV connected via wifi.
Computer A (Wired switch Connection) can only see computer B's (Wired switch Connection) music library.
Computer B (Wired switch Connection) can see both computer A's and computer C's (Wireless router connection) Music library.
Computer C (Wireless router connection)) can see computer B's (Wired switch Connection) music library.
Apple TV can see computer B and C.
The problem is that computer A Is the music computer That I want to stream throughout.
If computer A and B can see each other, and computer C and AppleTV can see computer B, then why can't everyone see computer A ?
Any response appreciated.