Crash when clearing "ans" variable in symbol table

[Michael Goffioul]

On 1/14/08, John W. Eaton <jwe at bevo.che.wisc.edu> wrote:
> Objects are pushed on the value_stack when functions are called
> recursively.  My guess is that you've found some way to have a
> recursive call that doesn't properly trigger the push, but still has a
> pop of the stack.

Will you have a look into this? Or could you give me some hints
where to look (I currently have no clue).
[Note that this is not my code; I just found the problem while testing
someone else's code; I have no more clues about the offending code]

Michael.