ClamWin: When opening program it selects drive D?

Hi Guys
This has always done this just forgot to ask,
when starting clamwin portable(run locally)
from Portable Apps folder(that is where I
installed it per John) It highlights my D
drive(dvd)no biggie just wondering why it
has always done this?It should highlight the
C drive.......I use XP Home Edition.
Thanks
Bill