DLL don't load libraries

[mourad]

Hello everybody, I've developped a Qt library (dll) whitch has 3 functions of connexion/close database and manipulation of data. When I want to test this dll and call it from another program, I can't connect to the database because the dll have not loaded the plugins of the connexion to the database (Ibase in my case). When I do

QStringList ActPathList = QCoreApplication::libraryPaths ();
         qDebug() <<  ActPathList.join("-");

QStringList ActPathList = QCoreApplication::libraryPaths ();
         qDebug() <<  ActPathList.join("-");

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alwyas ActPathList is null.
I've tried to do the same in a WindowForm projet and it works fine. I've checked the dll projet properties but I've not found anything abnormal.
I will be very thankfull if anyone can tell me where I'm wrong and what I must to do to resolve this problem.
Best regards

[jacek]

Does this "another program" create QApplication or QCoreApplication instance?