I am trying to synthesize a code using ISE which contains a component
fifo the fifo code is the following

-- synopsys translate_off
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
library UNISIM;
use UNISIM.VCOMPONENTS.ALL;
use UNISIM.VPKG.ALL;

entity ifo is
.....................
...............
end ifo

ARCHITECTURE st of ifo is
..........
.........
end st

-- synopsys translate_on

If I run the above code using ise it doesnt recognize the component at
all. If I remove the line sysnopsys translate_off then it gives me
following error
Library unit VPKG is not available in library UNISIM

any ideas?
Thanks
-D