Error: To run AOA the name of the AOA callback procedure should be assigned to suffix 'CallbackAOA' of 'Loesung'

While calculating a Sum-Function  I encountered a problem  (see error message below):

While using the power of X=1 and X=2 the model works perfectly however with any other number (also negative numbers) it displays the error below in red.

Function: 

Sum[p, 2 * (L1(p)+0.001)^(X) ] 

Using +0.001 to avoid any division by 0 (in case of X being negative).

L1(p) being a variable which is defined by a constraint L_1(p):

Sum[i,L(p,i)] + L1(p-1)= L1(p)

And L(p,i) in the constraint being a binary parameter.

To run AOA the name of the AOA callback procedure should be assigned to suffix 'CallbackAOA' of 'Loesung'. For example: Loesung.CallbackAOA := 'OuterApprox::BasicAlgorithm'; where 'OuterApprox' is the prefix of the Outer Approximation module.

Warning: Model status 13: Error no solution, Solver status 10: Error: Solver failure (see message window).

Thank your for any help.