Bad request's status 400

[Lupke]

Hi there,

Description:
I get 3 bad request error's status code 400 when testing the speed of my website.

VirtueMart Version:
1.1.2. stable

Joomla Version:
1.5.8.

Steps to replicate:
error 1:
components/com_virtuemart/fetchscript.php?gzip=1&amp,subdir[0]=/themes/default&amp,file[0]=theme.js&amp,subdir[1]=/js&amp,file[1]=sleight.js&amp,subdir[2]=/js/mootools&amp,file[2]=mootools-release-1.11.js&amp,subdir[3]=/js/mootools&amp,file[3]=mooPrompt.js

error 2:
components/com_virtuemart/fetchscript.php?gzip=1&amp,subdir[0]=/themes/default&amp,file[0]=theme.css&amp,subdir[1]=/js/mootools&amp,file[1]=mooPrompt.css

error 3:
components/com_virtuemart/fetchscript.php?gzip=1&amp,subdir[0]=/js&amp,file[0]=wz_tooltip.js

System info:
Windows xp sp3 (FF3+, IE7+, Opera 9+, Safari 3+, Chrome Beta)
phpMyAdmin - 2.9.1.1-Debian-8
PHP 5
Linux webserver

Can I do something about this? Does it slow down my website? Still learning...

regards,
Gabriel