Could not open database or xml outside qtcreator installation platform

I am running on windows 7 + qtcreator 2.0.1, and i am managing an sqlite database: here is the code:

The xml code has the same behaviour ..
This code works good into win7, so i compiled the app and moved it ( exe+dll ) to xp. I started the application and the db could not be found from the point of view of db.setdatabasename. I installed Qtcreator on xp, and then everything works. It seems that there must be another library hidden somewhere that has xml and database support What do i have to add to my project in order to support sqlite and xml out of the box?
Those are the file i have near my exe:
Application.db
libgcc_s_dw2-1.dll
mingwm10.dll
QtCore4.dll
QtCored4.dll
QtGui4.dll
QtGuid4.dll
QtNetwork4.dll
QtNetworkd4.dll
QtSql4.dll
QtSqld4.dll
QtXml4.dll
QtXmld4.dll
SpeedyInstaller2.exe
test.xml

Thanks :)

EDIT: moved to install and deployment, gerolf