Strange Installation Issue

Hi 2 u all . . .
Happy new year. .
For 3 days now (28-31 dec 2008) i was trying to install drupal at my pc but with no luck ( yes i m a noobie ).
I m using win xp pro sp3 with wamp5 plus i have modified the windows's hosts file ( windows/system23/etc/hosts) and the http-vhosts conf file from apache in order to use h t t p://w w w .mystestsites.com names instead of h t t p://localhost/mytestsite/

So with this modification i can use symbolic names for testing my sites like . mytestsite.gt or testsite.gt . . . i gave drupal the drupal.gt domain name. ( i use the .gt extension for every site i develop locally )
So everything works fine with that except with drupal.(such a dissapointment)
e.g joomla plays fine with localhost (127.0.0.1) i mean that i have installed and tested locally ( at my pc ) joomla at www.joomla.gt with no problem at all
(I ve done the same thing with prestashop , mambo and wordpress without any problem.)
So i followed my standard procedure and created a local folder at c:\wamp\www with the name drupal c:\wamp\www\drupal ( changed permissions)
added

NameVirtualHost 127.0.0.1

ServerName www.drupal.gt
DocumentRoot "C:/wamp/www/drupal"

at apache http-vhosts conf file and finally
changed hosts file ( from windows) by adding a new line
127.0.0.1 www.drupal.gt
restarted my pc just in case cleared all my web browser caching information.. and then tried once more . but no luck at all . . . oh i also activated javascript added website exceptions (trust this site etc ) from mozilla options . . .
used every solution that have been mentioned around here (i mean within this forum) . . .
e.g changed my php.ini file post max size from 8M to 16M or 64 or 128 but with no luck.. .
changed the status from the system mysql table
i also changed php code with the SQL query and the error message at 315 line
http://drupal.org/node/260908
http://drupal.org/node/223160#comment-776257
http://drupal.org/node/1213

BUT for once more
WITH NO LUCK

.
drupal just didnt want to be installed at my pc.

So after 3 days of wondering i thought of trying a clean installation from
h t t p ://localhost/drupal
so i dropped the drupal database created a new one deleted the drupal folder downloaded a new one and started from scratch.

Guess what . . .
No problem at all.

So after the installation i tried to login from w w w .drupal.gt but with no luck for once more (i still can log in from h t t p://localhost/drupal with no prob.).

So i came to this conclusion localhost or 127.0.0.1 is the problem and the php code that comes with it. How is it possible to get Zero ( especially from sql statements ) errors when u use h t t p : / / localhost/drupal and getting frustated ( when u solve something another thing shows up ) when u try to install drupal from w w w . drupal . gt .

I m not an expert PHP programmer but i believe that this has to do with sessions or how the localhost or 127.0.0.1 address are used in order to gain access during the installation .

P.S:Sorry about the joomla ref :D . but i have spent days of reading articles about joomla and drupal in order to decide with which cms to use.

Ps.2 excuse my poor english.