Comment 6 for bug 830435

Strange, are you using the main ubuntu repositories or some other private one providing a broken qt package?
This package is fine:
https://launchpadlibrarian.net/74037884/libqtcore4_4.7.2-0ubuntu6.2_amd64.deb

$ md5sum libqtcore4_4.7.2-0ubuntu6.2_amd64.deb
9316a61423a66497b0b879f88831f80b libqtcore4_4.7.2-0ubuntu6.2_amd64.deb

$ dpkg -x libqtcore4_4.7.2-0ubuntu6.2_amd64.deb /tmp/qtcore4
$ nm --dynamic /tmp/qtcore4/usr/lib/libQtCore.so.4 | grep heckWin
000000000016afd0 T _ZN14QObjectPrivate15checkWindowRoleEv

$ ldd -r usr/lib/libQtCore.so.4 2>&1 | grep undef

please install the ok package:
wget https://launchpadlibrarian.net/74037884/libqtcore4_4.7.2-0ubuntu6.2_amd64.deb
sudo dpkg -i libqtcore4_4.7.2-0ubuntu6.2_amd64.deb
sudo apt-get install -f