This error occurs when Windows denies DPL's request for a data item sent over a DDE link. The problem is often intermittent, depending on the specific computer the model is run on and the other applications running. Usually the amount of DDE message traffic is large so that Windows has trouble keeping up.
One way to fix the problem is to run only the applications which you need for the analysis (i.e., DPL and Excel).
If it is possible to reduce the size of the tree or use discrete tree simulation, this may help. To completely avoid the problem, convert the spreadsheet to DPL code so no DDE communication is necessary. See Converting Spreadsheets to DPL Programs
Versions: DPL Professional, DPL Enterprise, DPL Portfolio