I am no longer observing the crash using the latest PyQt4 Windows installer
including Qt 5.0.2.

I am observing the same issue over here on Windows. eric5 is working fine with
Qt 5.0.x on Linux and Mac OS X. Therefore I am considering this a Qt or PyQt
installer issue. Nevertheless, any further hint that could point in the right
direction to elaborate a work around are welcome.

Uninstalling Qt5.0.1 and associated PyQt, and installing qt-win-opensource-4.8.4-
vs2010.exe and PyQt4-4.10-gpl-Py3.3-Qt4.8.4-x32.exe, uninstalling and reinstalling 
Eric5, allows Eric5 to work perfectly on that same machine.

Details:
after eric5 starts, I can use the python shell, but any action involving tooltip, 
opening a dialog, will cause a crash with the message "pythonw.exe has stopped 
working"
eric5_configure launches correctly.

On Windows 7, after successful installation of Python33 32bits, Qt5.0.1, 
PyQt/SIP/Scintilla from sources, and succesfully intall of eric5, eric5 IDE can 
start.
After eric5 starts, I can use the python shell, but any action involving 
tooltip, opening a dialog, or pretty much anything else will cause a crash with 
the message "pythonw.exe has stopped working"
eric5_configure launches correctly.

Versions:
Windows 7 64 bits
Python 3.3.1-32bit
2.1.8 win32 for Py3.3 32bit
qt-windows-opensource-5.0.1-msvc2010_32-x86-offline
sip-4.14.5 (compiled from source with MSV C++ 2010)
PyQt4-4.10-gpl-Py3.3-Qt5.0.1-x32-2 (compiled from source with MSV C++ 2010 to go 
around the missing QtHelp issue)
QScintilla-gpl-2.7.1 (compiled from source with MSV C++ 2010)
eric5-5.3.2