Portable DOpus - English Language Pack not found

I have been using portable DOpus on a U3 thumbdrive for about a week.
Last night I used the U3 to remove the drive (as usual).
This morning, when I inserted the thumbdrive DOpus could not start, and issued the message "The English Language Pack could no be found"

I happen to be on a PC that I had used to evaluate DOpus and I can see the language packs still on that machine.

Can I copy the language pack(s) to my thumbdrive?
If so, into which directory?

Thank you,


Couldn't find where to put the language pack.

Over the weekend, re-exported to the USB from home computer.
Everything works now, but I'm worried about the next time I try the portable version.