Random crashes Calc

users
#1

facturesAvecErreurs.ods
<http://nabble.documentfoundation.org/file/n4098348/facturesAvecErreurs.ods>
hello all,
my app crash randomly!
using the drop down list "Nouvelle Facture" to choose a client, then the
button "Iprimer Facture"
without changing anything else, I crash after 5-60 manipulations.
confusion between getValue, getString, and setValue, setString can cause
this crash?
do I have to manually release the memory somewhere?
I enclose the application calc offending
many thanks