I am struggling to understand your network setup, to me it looks completely mis-configured.
The "Bridge" I imagine is a Media Bridge (operating at layer 3) and not a Network Bridge (which operates at layer2)?
Your PC has two network ports, both of which need IP addresses, usually the second port is on a different subnet to the first (called multihomed) to allow it to sit on two different networks at once. No two ethernet ports can use the same IP address - it seemed at one point to have both the Bridge and PC on the same address, which would cause huge network issues!. So your PC and Bridge would need three IP addresses in total.
If the two PC ports are on the same network, the PC will randomly choose to use one or the other for each communication, believing they are identical and can both see the whole network - however, only one of these ports is actually connected to the correct network (the one with the router). The PC will be throwing a lot of errors since it believe both ports are on the same network - which they are not. You can't just plug something into one port and expect the PC to turn into an ethernet switch and pass incoming traffic to the other port.
The easiest way to sort this is to forget the second PC ethernet port and plug your bridge into a switch connected to the router.
If you can't do this, the the second port should be on a different network (along with your Bridge e.g. 192.168.10.0/24). However, doing this will have consequences, key of which is DNLA will not work between the Bridge and Router networks, since it uses Broadcasts which are prevented from traversing between subnets. Also you may also need to set up routing tables to manage traffic flow - I am guessing with what you have said so far that this is probably way beyond your level of IT knowledge!