Preparing to unpack .../libqwt5-qt4_5.2.3-1_i386.deb ...
Unpacking libqwt5-qt4 (5.2.3-1) ...
Selecting previously unselected package libqwt5-qt4-dev.
Preparing to unpack .../libqwt5-qt4-dev_5.2.3-1_i386.deb ...
Unpacking libqwt5-qt4-dev (5.2.3-1) ...
dpkg: error processing archive /var/cache/apt/archives/libqwt5-qt4-dev_5.2.3-1_i386.deb (--unpack):
 trying to overwrite '/usr/lib/i386-linux-gnu/qt4/plugins/designer/libqwt_designer_plugin.so', which is also in package libqwt6 6.1.1-0ubuntu1