[imp] Imp Dynamic View suck at "loading..."

[Terry Carmen]

Both the folder tree and the message list pane simply say  
"Loading...", but nothing ever loads.

All components are up to date with the "check for newer versions" button:
Horde Groupware Webmail Edition 4.0.8
Horde Horde (horde) 4.0.15
Mail Mail (imp) 5.0.22

There are no errors in the browser's javascript console, the system  
error log or the apache error log.

I cranked up the  log level in Horde to "debug" and it shows tons of  
stuff, but nothing that pops out as a problem.

I'm out of ideas as to what to look at or how to fix this. Any suggestions?

Thanks,

Terry