This program that I had written compiles fine in other distro's with qt4 installed. However, I get the following errors: qmake -project (works fine) qmake (works fine) make (gives this output): g++ -c -pipe -fno-strict-aliasing -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_CORE_LIB -DQT_GUI_LIB -DQT_QT3SUPPORT_LIB -DQT3_SUPPORT -DQT_SHARED -I/usr/share/qt/mkspecs/default -I. -I/usr/include/Qt3Support -I/usr/include/QtGui -I/usr/include/QtCore -I/usr/include -I. -I../libs -I"`pg_config --includedir`" -I"/usr/include/pqxx" -I. -I. -o patientselect.o patientselect.cpp patientselect.cpp: In member function ‘void PatientSelect::updateTable()’: patientselect.cpp:183: error: ‘class QString’ has no member named ‘toStdString’ patientselect.cpp:189: error: ‘class QString’ has no member named ‘toStdString’ patientselect.cpp:194: error: ‘class QString’ has no member named ‘toStdString’ patientselect.cpp:214: error: ‘class QString’ has no member named ‘toStdString’ patientselect.cpp:216: error: ‘class QString’ has no member named ‘toStdString’ patientselect.cpp:218: error: ‘class QString’ has no member named ‘toStdString’ patientselect.cpp:250: error: ‘fromStdString’ is not a member of ‘QString’ patientselect.cpp:257: error: ‘fromStdString’ is not a member of ‘QString’ make: *** [patientselect.o] Error 1 QString is included, and as I said, the source does compile. I can't tell where it is looking for the QString class at.