Migrating docs from 3.08 to 3.16

[Tod Olson]

I've just upgraded my Lout from 3.08 to 3.16, and I'm having a few
document problems since the upgrade.

One example: a document does @SysInclude { doc }, and the following
is in my mydefs file:

    def @LabeledBox
      left x
      named @Height { .9f }
      named @Width { 1i }
      right y
    {
      @OneRow {
        @Box @Height @High @Width @Wide { @Center y }
        //2p
        @Width @Wide { @Center x }
      }
    }

Lout 3.08 was silent, but 3.16 now reports the following errors wrt
this def:

   22,5: symbol @Box unknown or misspelt
   22,39: symbol @Center unknown or misspelt
   24,20: symbol @Center unknown or misspelt
   30,19 fatal error: exiting now

I'm a bit surprised: since @Box is exported by BasicSetup, I expect it 
to be available inside definitions in mydefs.

Is the problem evident to more experienced hands (and eyes)?

Thanks.

Tod A. Olson                        "How do you know I'm mad?" said Alice.
address@hidden               "If you weren't mad, you wouldn't have
The University of Chicago Library    come here," said the Cat.