help with room to room sharing

last week i woke up to find that my replays saw each other 4504,5504,5040 then they disappeared the 5040 i did 243 zones then 17 the 5040 will see the 4504 but says its off line.teh 5504 see no other units and the4504 has no way to find other units . i have a linksys befsr41 wired router .i have dvarchive but do i need it to share room to room?and what do i need?pat

to tell you the truth i dont know i got up one morning to watch something and noticed the option of other replays in guide,i accessed the kitchen one from bedroom and was able to watch a show i had one there but then the next time i tried it dissappeared when i accessed it i have all three hard wired into the router {linksys befsr41} along with my computer then the router directly to modem .ive done 243 zones 17 and the 5504 see the 5040 but says its offine sometimes the 5040 will see the 5504 says same thing.ive rebooted all three , rebooted router and modem.right now i can ping all three and dvarchive sees all.if i could though id like to be able to watch on one replay something i have on other without going thru dvarchive.pat