Initdb error during silent install on windows 2000

Hi All:

I am getting following error from initdb during silent installation of 8.0.1:

creating directory C:/Program Files/PostgreSQL/8.0/data/global ... initdb: could not create directory "C:/Program Files": File exists

I have searched about this issue and usually this happens due to a permission problem. I have checked the permission they look fine to me. Also I have used same install on at least 15 other PCs (Mix of win 2K and win xp) and it worked fine for each one except this one. Any ideas what might be the problem? Following are the permissions on this PC (BTW other PCs have exactly same permissions and install works without any problem):

C:\: Everyone => Allow FullControl, No Deny
C:\Program Files: Group User => Allow Read &Execute, List Folder Content, Read. No Deny

The user postgres is member of group Users.

Thanks in advance for your help.

Thanks

Karim