Unable to compile EP20K300EQC240-2X device using Quartus 9.0sp2 Web edition on Windows XP.

It does need a license, contrary to what is advertised. When I had reported the error, the XP machine had absolutely no Quartus license. The design was not compiling, as described in the original complaint. Then, I generated a companion license from the Intel Self Service Licensing Center (I included the XP Machine's NIC ID). I copied the license locally on to the XP machine, and pointed the Quartus 9.0sp license to the same. It worked right away.

Intel / Altera needs to fix this issue, or simply state on their website that a license IS ACTUALLY required. But that's asking too much, isn't it?