To work around the problem, open the file C:\Xilinx\12.1\ISE_DS\EDK\sw\XilinxProcessorIPLib\drivers\usb_v3_00_a\src\xusb_intr.c in a text editor.
Edit line 303 from:
UsbInstPtr->HandlerFunc(UsbInstPtr->HandlerRef
to:
UsbInstPtr->ErrHandlerFunc(UsbInstPtr->ErrHandlerRef
This issue has been fixed in v3.01.a of the driver, which will be available with the EDK 12.2 release.