Funny or actually not funny enough come to think of it I just ran into the same error trying to install a Jack audio server tool compiled with QT on my knoppix hd and solved the QT issue's but still can't make jack work? so heres hoping you or someone out there knows jack LOL

anyway QT issues solved by
adding /usr/shared/qt3/bin to path
and then
export QTDIR=/usr/share/qt3
check with echo $QTDIR it should list the path if all is well

Any help with Jack and ardour greatly appreciated I can't build jack or the QT jack control however jack is installed with the ardour debian package? just cant seem to use it?
Thanks
ED