Starting PostgreSQL on WinXP is not working

Hi, i'm working with PostgreSQL for a long time (about three years), but always on Linux box. But recently, I had to intall PostgreSQL on a WinXP machine!
The installation works fine, although the starting service did not works in the finalization of the installation! The installation was done in a WinXP SP1 as a service!
My problem is that I installed with admin rights, but created the user postgres for the system and user postgres for the database. The user postgres for the system is supposed to be used to start the service, but i think it is not happening, the system tries to start the service with the user that login in the system (the admin). If I trie to start the service with a user without admin privileges it gives me this error:

2005-06-08 15:14:07 NOTICE: Unknown win32 socket error code: 10106
2005-06-08 15:14:07 LOG: could not create IPv4 socket: Invalid argument
2005-06-08 15:14:07 WARNING: could not create listen socket for "localhost"
2005-06-08 15:14:07 FATAL: no socket created for listening

I googled a lot and dind't find anything with this kind of error. So, I really need some help!
Thanks a lot!!