Ok, I've done some reading. First of all please run otool on the wwidgets plugin (libwwwidgetsplugin.dylib) and post the result here. Then run otool on the widget library (libwwwidgets4.dylib) and post the result as well. Finally post the absolute path to:
1. Qt libraries
2. libwwwidgets4.dylib
3. libwwwidgetsplugin.dylib

You'll need all that information to use a tool called install_name_tool. You can enter its name in Qt Assistant to learn about what it does.