You really should use a more recent version of spectre - you can use this in conjunction with an older environment, although a version from May 2003 is pretty old... newer versions should be available to most universities - are you part of Europractice?
Note that there was an issue with the ddx() usage in the PSP veriloga model which I worked on a few months ago - it was fixed in November 2008 in MMSIM (the stream containing spectre) 6.2.1.390 and also 07.01.162.isr14
Even with these builds, you have to do:
Code:setenv CDS_AHDL_IGNORE_RESTRICT YES
because the code uses ddx() in a conditional statement (if the code is the same as the one I was looking at - it looks as if it is).
Regards,
Andrew.