I need someone that helps me with C++/QT debugging

I want to update an older software with new QT and QWT Framworks. I have not much experience in C++ but I accomplished some things already. I successfully built the IDE with new QT and QWT Frameworks. I updated most of the code from char to wchar. I took out the features that weren't wanted anymore.

I can compile it and execute it but now I have a problem with the QMutexLocker when it tries to execute an SQL-query. I believe either I didn't install something correctly, the updated code has some character-set mistake (unicode/ansi) or there are some objects->memory problems. I tried several ideas but none of them worked. QMutexLocker worked in a test-project.