Qwt on Windows Xp

[mrdebug]

In order to use Qwt in a Windows Xp project I have inserted these rows in my .pro file:
@ LIBS += ../../qwt-6.0.2/lib/libqwt.a
LIBS += ../../qwt-6.0.2/lib/libqwtmathml.a
INCLUDEPATH += ../../qwt-6.0.2/src
@

In the past all was ok but now, but now, after the upgrade of qt sdk, I can compile correctly my application without any error but the application does not starts.
Can you help my? I have searched the solution during all the day!

[VanDerSam]

You are attempting to run executable from the IDE or directory?

[mrdebug]

From ide I obtain a crash with some result code, from directory (I have copied the required dll) I obtain a error like "application not initialized"

[mrdebug]

Solved adding
DEFINES += QWT_DLL
in .pro file