Problem running forms

Hi
Using Oracle9i Developer suite

Everytime i run a form from form builders it opens the internet explorer window with the following url
http://%%20"http://mango:8888/forms90/f90servlet?form=F:\BCSD\ora\forms\main_menu.fmx&userid=trial/pass@orcl&buffer_records=NO&debug_messages=NO&array=YES&query_only=NO&quiet=NO&RENDER=YES"

The form is not displayed on the screen

If i remove http://%%20" from the start of the url the form is displayed correctly.

Could someone please tell me if this is a configuration issue and how i go about solving it.