Similar errors will be issued for other cores as well.
The problem is in the pre-compiled MXE library zip file for VHDL. It has an erroneous path of:
The correct path should be :
To work around this problem, correct the erroneous path by eliminating the redundant "xilinxcorelib" directory in your system.
Another work-around is to download and re-install the new VHDL zip file that was released on October 20, 2001. If you are concerned about having enough disk space, delete the entire xilinx\vhdl\xilinxcorelib\*.* directory before installing the new zip file.