Sorry!
Got a more pressing problem than setting up custom campaigns.
Clients are getting this message when connecting to our (Mach5//) Pro server. Anyone seen it before and remember the cause? Of course, someone’s posted about it in the other forum - sod all good that’s doing me now!
Aha! I’ve just found that Google caches the old site… a bit anyway. Example:
I Googled this error and got a hit on the old forums:
community.enemyterritory.com/forums/showthread.php?t=29908 - cached.
Click on the ‘cached’ link and it took me to a copy of the forum post 
Probably some pk4s on the server that shouldn’t be there and aren’t being offered for auto-download.
I think that error indicates that the server isn’t offering any downloads. Also check the client console after getting such errors, there might be more info there.
Check that your server is actually running with the autodownload settings enabled, by investigating the etqwdedconfig.cfg file. Usually found in base or etqwpro dir in server save path.
Thanks for the fast responses.
The problem was that I’d installed some custom maps and campaign configs to the server’s base directory. I cleaned them out and all seems to be working again.
So, where does custom content live?
It should work ok to put map files in the base dir, most people do. The campaign file might also go there, but it’s better to have them in the mod dir, to make sure the mod doesn’t override anything inside it.
Frankly I’m not 100% sure if that error means download is off or something else.