4.5 beta 6 new install doesn't set upload directories in windows environment

copied from http://forum.civicrm.org/index.php/topic,33847

My home pc runs windows 7. I was having some problems with my test install so deleted the drupal folder and the civicrm and drupal databases, so effectively this was a new install.

Everything seemed to install correctly, but I was still getting (at least) the first two problems I did in http://forum.civicrm.org/index.php/topic,33783 namely

Arrow image broken on administer menu (image attached) Also applies to other places it should appear on navigation menu
Administer>CiviCase>Case Type takes me to a blank screen(Image attached)

With help from Coleman, it was tracked down to Administer > system settings > directories just being defined as upload/, persist/contribute/ and custom/ . When I changed these to absolute file locations ie prefixed with C:/xampp/htdocs/drupal/sites/default/files/civicrm/ the problems disappeared.

Based on the blurb on the top of this pages in civicrm.setting.php I found.

define( 'CIVICRM_TEMPLATE_COMPILEDIR', 'C:/xampp/htdocs/drupal\\sites\\default\\files\\civicrm\\templates_c
' )

when I go to Cleanup Caches and Update Paths , the system suggests C:/xampp/htdocs/drupal\sites\default\files\civicrm\templates_c\en_US\ as the New Base Directory although the old base directory is actually correct.

I have installed civicrm several times on windows over the last three years and have never had to alter the directory settings nor had this problem until the 4.5beta5 install I tried on wordpress and this 4.5beta6 install on drupal.