There is a problem in the Embedded Tri-mode Ethernet MAC Wrapper v1.0 when the EMAC is used with the DCR option as the host interface. Specifically, the VHDL and Verilog wrapper (core_name_vhd and core_name.v) does not have the host interface enabled even though DCR is selected.
A patch is available that correctly enables the host interface when the DCR interface is selected.
To obtain this fix, install the patch that is available in the Embedded Tri-mode Ethernet MAC Wrapper v1.0 Release Notes and Known Issues Answer Record (Xilinx Answer 20193).
Another way to work around this issue is to change the assignment of the "has_host_0_i" and "has_host_1_i" signals from 0 to 1 in the wrapper file.