i am using script file(.scr file) to pass value 

C:\Program Files\AutoCAD LT 2006\aclt C:\1.dwg /b c:\script.scr
first time when i pass value value ,autocad lt will open and in that i am inserting some dwg file

if i pass value for second time its opening new autocad lt window and it will inset the drawing

i dont want to open new window if autocadlt is open already i want to insert dwg file in active winodw