[developers] Treebanking in Logon

[Bart Cramer]

Dear developers,

I recently moved from the common LKB/itsdb set-up to the Logon tree,
but found something funny. Using the same combination of PET-parsed
profile and grammar, the old set-up was working fine, but the Logon
set-up was working 100% until the annotation window pops up. That
window says at the top 'analyzing parse forest, please wait'. The lisp
window in emacs
indicates that he found the parses, the edges, no decisions (correct,
I think), and then says: "podium-loop(): Non-structure argument NIL
passed to ref of structure slot 2."  I have no idea what that means,
or what could be the cause of this. I used the same version of the
grammar when parsing and treebanking.

What does this error message mean, and why does the treebanking fail?

Best,

Bart.