Warning: Qt: Session management error: None of the authentication protocols specified are supported

backtrace: ('warning from Qt')
======= BEGIN OF BACKTRACE =====
[0] ./scc(_Z14printBacktraceRK7QString+0x9b) [0x8185b77]
[1] ./scc(_Z14messageHandler9QtMsgTypePKc+0x23a) [0x8186684]
[2] /usr/lib/libQtCore.so.4(_Z17qt_message_output9QtMsgTypePKc+0x35) [0xb6aacf65]
[3] /usr/lib/libQtCore.so.4(+0x6716a) [0xb6aad16a]
[4] /usr/lib/libQtCore.so.4(_Z8qWarningPKcz+0x19) [0xb6aad349]
[5] /usr/lib/libQtGui.so.4(_ZN15QSessionManagerC1EP12QApplicationR7QStringS3_+0x3c8) [0xb6f676c8]
[6] /usr/lib/libQtGui.so.4(_ZN19QApplicationPrivate10initializeEv+0xa9) [0xb6ee95a9]
[7] /usr/lib/libQtGui.so.4(_ZN19QApplicationPrivate9constructEP9_XDisplaymm+0x72) [0xb6ee96e2]
[8] /usr/lib/libQtGui.so.4(_ZN12QApplicationC2ERiPPci+0x83) [0xb6eea6d3]
[9] ./scc(_ZN17SingleApplicationC1ERiPPc7QString+0x28) [0x80a76a4]
[10] ./scc(main+0x61) [0x809959d]
[11] /lib/i686/cmov/libc.so.6(__libc_start_main+0xe6) [0xb65a9c76]
[12] ./scc() [0x80830e1]
======= END OF BACKTRACE  ======