Error when executing Qt application on Win7: possible issue with libstdc++-6.dll?

[sol_kanar]

I have a Qt project that is working well under Linux, and I am trying to run it under Windows 7 64 bit. I am using Qt 5.1.1 and mingw 4.8.

In order to create the executable starting from the .pro file, I followed the subsequent steps:
- run qmake.exe from directory Qt/5.1.1/mingw48_32/bin
- run mingw32-make.exe from directory Qt/Tools/mingw48_32/bin
- put all needed .dlls inside the folder with the freshly created .exe of my application. I took the .dlls from Qt/5.1.1/mingw48_32/bin. The libraries are:
-- icudt51.dll
-- icuin51.dll
-- icuuc51.dll
-- libstdc++-6.dll
-- libwinpthread-1.dll
-- Qt5Core.dll
-- Qt5Gui.dll
-- Qt5QWidgets.dll

When I try to run my application, it crashes immediately with the following error:

Problem signature:
Problem Event Name: APPCRASH
Application Name: ugp3-population-inspector.exe
Application Version: 0.0.0.0
Application Timestamp: 529b97e7
Fault Module Name: libstdc++-6.dll
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 516ee7b6
Exception Code: c0000005
Exception Offset: 00043f17
OS Version: 6.1.7601.2.1.0.768.3
Locale ID: 1036
Additional Information 1: 3a5f
Additional Information 2: 3a5f3876e9d420f8f9257cedd5068646
Additional Information 3: 58bf
Additional Information 4: 58bfe2891c811f25e4b9e96b50dd180b

So, it looks like there is some trouble with libstdc++-6.dll...but I don't really understand the issue.

Can anyone help me? Thanks in advance :-)