On a GL-X3000 running 0704release5 firmware, I consistently get the message below from the Luci interface to opkg. I'm guessing that a corrupt opkg file needs to be rebuilt but I've no idea which one, or how to rebuild. Suggestions welcome 
Hello,
Already inform to R&D to check.
Hi,
This issue is improved.
Thanks Bruce.
I just tried "Update lists..." on my X3000 and there were no error messages.
Cheers
Sean