Johan,
the reason for these messages produced by a subscription are explained in
step-1. The proximal cause is that somewhere an object is being destroyed to
which another object still holds a pointer. That can happen as in step-1
because objects are declared in the wrong order, or sometimes if an unrelated
exception is thrown and not caught, leading to objects on the stack being
destroyed in the wrong order.
What the cause in your case is I don't know -- why don't you send us your
little test program so we can take a look?
W.
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Wolfgang Bangerth email: [EMAIL PROTECTED]
www: http://www.math.tamu.edu/~bangerth/
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