FTBFS: conversion errors

During rebuild testing:

cd /build/buildd/qzion-0.4.0/obj-i486-linux-gnu/python && /usr/bin/g++ -Dpython_module_qzion_qzion_EXPORTS -DQT_DLL -DQT_WEBKIT_LIB -DQT_GUI_LIB -DQT_CORE_LIB -DQT_NO_DEBUG -g -O2 -g -Wall -O2 -Wall -O2 -g -DQT_NO_DEBUG_OUTPUT -fPIC -I/usr/include/python2.6 -I/build/buildd/qzion-0.4.0/python/../src/common -I/usr/include/qt4 -I/usr/include/qt4/QtWebKit -I/usr/include/qt4/QtGui -I/usr/include/qt4/QtCore -o CMakeFiles/python_module_qzion_qzion.dir/qzion/sipqzionpart0.cpp.o -c /build/buildd/qzion-0.4.0/obj-i486-linux-gnu/python/qzion/sipqzionpart0.cpp
/build/buildd/qzion-0.4.0/python/qzion/qzionobject.sip: In function 'const sipTypeDef* sipSubClass_QZionObject(void**)':
/build/buildd/qzion-0.4.0/python/qzion/qzionobject.sip:22: error: invalid conversion from 'const char*' to 'char*'
/build/buildd/qzion-0.4.0/python/qzion/qzionobject.sip:22: error: invalid conversion from 'const char*' to 'char*'
/build/buildd/qzion-0.4.0/python/qzion/qzionobject.sip:22: error: invalid conversion from 'const char*' to 'char*'
/build/buildd/qzion-0.4.0/python/qzion/qzionobject.sip:22: error: invalid conversion from 'const char*' to 'char*'
/build/buildd/qzion-0.4.0/python/qzion/qzionobject.sip:22: error: invalid conversion from 'const char*' to 'char*'
make[3]: *** [python/CMakeFiles/python_module_qzion_qzion.dir/qzion/sipqzionpart0.cpp.o] Error 1