Some of the important bits were missed in the machine translation I think
From what it says on the page, it's an entirely new song specially made for J-WAVE.
A quick and not quite so dirty (mmm) translation of
http://trafficjpn.com/underworld/news.html:
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Underworld's new song "Parc" picked as J-WAVE's 20th anniversary song! On-air from 7th of May!!
To celebrate J-WAVE's historic 20th year since beginning broadcast, Underworld's new track "Parc" has been picked as the "20th J-WAVE Anniversary Song"!
This song was produced as a present from Underworld, and from the 7th of May will be broadcast on the J-WAVE program in a world first.
Underworld have been chosen as a FUJI ROCK FESTIVAL '08 (Sat 26th/Jul) headlining act. It's still 3 months until then, but until then the Japanese fans will receive this special present. Please tune in to enjoy!!
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- Matthew