What is stack overrun?

[Redsandro]

Sometimes a script sais:

Unable to execute script at line 0. Stack overrun

But most of the time there's no problem.

What causes this? If the script stops at line 0, I cannot incorporate any error catching code.
There's not a hint about where to start thinking. Anyone experienced these messages?

[Mylenium]

What are you doing in your script? There must be a reason for the leaky behavior...

Mylenium

[Redsandro]

I am walking through items in the render queue.
The render queue does not need to be selected or even visible, but in the mean time I found that this error only pops up if a layer is selected.