Error WL 416

[Ulrich Mende]

Hi workflowers,
at this sweltering day here in Munich one of our workflows at production
system is running into an error WL 416 : "No successor '' (space) for
case node 400". Out of 200 workflows of the same task, same version 150
run well, the rest goes into error.
 
What is mystery:
- our workflow definition has no node with number 400
- the workflow stops at the synchronization point ("endcase")
  of a case node 70, the case variable is always filled with a
  valid value
 
I am afraid that the error message is misleading.
 
Any suggestions? Thank you in advance.
 
Uli Mende