Orbit Downloader Portable

[jaae]

Hello,
I'm using Firefox 3.6.8 on a windows xp platform. I have a portable version of Orbit Downloader on an external harddrive that I use on several computers. Integration of Firefox with portable Orbit Downloader is achieved through Flashgot (latest version). In the command line arguments template I use [URL] and [POST] as arguments, and this works very well.
The only trouble I have is with adding new url's, while the curent one is still downloading. Then i get the message "Another OrbitDownloader is running. Close OrbitDownloader before running OrbitDownloader Portable". Orbit Downloader is NOT installed on the pc, it is only present on the external HD.
Is there a way of telling flashgot to ADD new url's to the download cue, rather than starting up a new instance of the download manager?

Many thanks for any help you can offer,

Jaae