Did u try to convert this to 2007 format? I believe security is now redundant in that or open the mdb inside 2007. Maybe you need to specify the path of the mdw file then
"msaccess path" "c:\mydb.mdb" /wrkgrp "c:\mydb.mdw"
replace "msaccess path" with the full path of msaccess.exe (2007 version) eg c:\program files\microsoft office\...
replace c:\mydb.mdb with your path c:\documents and settings\administrator etc
and the same with c:\mydb.mdw
Best to create a shortcut to do this