Valid Magnetics for W5100A

I am using a TG110-S050N2 transformer. It seems lose TCP/IP connection after a few minutes but only with a network server that has a i350 intel chipset. It works just fine with other NIC adapters. Is the TG110-S050N2 compatible with the W5100. If I place a Network Switch between the W5100 and the PC with the i350 NIC the communication works well.