Cabling issues in new home?

Dear all, I understand that it is not considered best practice to ask two questions in the same post, however I fear that these two problems might be linked by an insufficient home cabling therefore I am taking the liberty to do so:

We have moved into a new home and took our multiroom system with us. In the new house, all Masterlink connections are not realised using the old-fashioned Masterlink cables, but some shiny Ethernet-looking RJ45 connections ending in a ML distribution switch somewhere under the roof.

Everything that worked in the old home works fine, except for one thing:

a) N.MUSIC does not work anymore: PC is connected to BeoPort using USB, BeoPort is attached directly to ML distribution switch, to which audio master Beosound is attached as well. Chosing N.MUSIC from any room (irrelevant if master or link room) will result in hearing the desired sound for a second, then the SW crashing / becoming irresponsive on the PC. I tested this with two BeoPorts, one Mac, one Windows PC, to different SW on the Mac and the original B&O SW. Issue appears as well if I connect BS9000 directly to a ML distribution switch in the master room and BeoPort to same ML distribution switch.

b) I can't claim this worked in the old house because it was not configured the same way. One of the rooms is unreachable for cable ML, therefore I purchased two used Wireless Ones. So: Beolab 3500 is connected to Wireless 1 in link room, which connects to transmitting Wireless 1 attached directly to ML distribution switch under the roof, to which Beosound 9000 is attached as described in a). Connection between two Wireless is ok, connecting green, then switching to standby red. When I choose a source on Beolab 3500, source name is shortly indicated on BeoLab 3500, then screen turns blank. Wireless does not even get out of Standby.

I will try to upload a drawing when I am at home but I hope I was clear enough anyway.

Kind regards

Stefna