Tested the server connected to the router. Swapped cables, tried it on the other switch. Same deal. Tried some more drivers. Messed things up I think a little, started having problems with a single port transferring. I think the problem is in the driver. The Broadcom management console that comes with the driver crashes everytime I try to load it. I think that's the key for the bridge to work. With the OS being newer than the hardware, I think the server is at least 5 years old, they just stopped support on the NICs and there's no good driver for Server 12. I may swap out OS drives and run a test by installing Server 08 and see if that might fix it. I'm not a real huge fan of Server 12 anyway.
The SC430 also has a Broadcom NIC, single port, running Server 08 and I installed that driver and the Broadcom console works fine.
For now I just installed a PCI NIC on the T300 so I wouldn't have to deal with this Broadcom stuff now. It will work fine for everything except transferring files from a specific folder to the Server 08 server. Tested the problem files on the HTPC and Notebook, both transferred fine. And it will transfer files from elsewhere on the shared drive to Server 08 fine.
There's always something.