I built my dartclient manually with the following output:

[ 72%] Built target MitkIGTTestDriver
/usr/bin/ld: cannot find -lopencv_features2d
/usr/bin/ld: cannot find -lopencv_gpu
/usr/bin/ld: cannot find -lopencv_calib3d
/usr/bin/ld: cannot find -lopencv_objdetect
/usr/bin/ld: cannot find -lopencv_highgui
/usr/bin/ld: cannot find -lopencv_legacy
/usr/bin/ld: cannot find -lopencv_contrib
collect2: ld returned 1 exit status
make[2]: * [bin/libmitkOpenCVVideoSupport.so] Error 1
/make[1]: * [Modules/OpenCVVideoSupport/CMakeFiles/mitkOpenCVVideoSupport.dir/all] Error 2usr
/bin/ld: cannot find -make[1]: lopencv_features2d*** Waiting for unfinished jobs....

/usr/bin/ld: cannot find -lopencv_gpu
/usr/bin/ld: cannot find -lopencv_calib3d
/usr/bin/ld: cannot find -lopencv_objdetect
/usr/bin/ld: cannot find -lopencv_highgui
/usr/bin/ld: cannot find -lopencv_legacy
/usr/bin/ld: cannot find -lopencv_contrib
collect2: ld returned 1 exit status
make[2]: * [bin/libmitkToFProcessing.so] Error 1
make[1]: * [Modules/ToFProcessing/CMakeFiles/mitkToFProcessing.dir/all] Error 2
[ 80%] Built target QmitkExt

make: *** [all] Error 2

I think this is OpenCV related and not ToFProcessing. ToFProcessing is just 1 out of 3 or 4 modules using OpenCV.

I cannot even build OpenCV:

[ 75%] Building CXX object modules/highgui/CMakeFiles/opencv_highgui.dir/src/cap_v4l.o
/usr/local/thomas/DartClients/NightlyExternal/MITK-Superbuild-Release-nightly/CMakeExternals/Source/OpenCV/modules/highgui/src/cap_v4l.cpp:217:28: fatal error: linux/videodev.h: No such file or directory
compilation terminated.
make[2]: * [modules/highgui/CMakeFiles/opencv_highgui.dir/src/cap_v4l.o] Error 1
make[1]: * [modules/highgui/CMakeFiles/opencv_highgui.dir/all] Error 2
make: *** [all] Error 2

This is actually an OpenCV bug. OpenCV is not running with ubuntu 11.04 yet.

Here is a solution:
http://tech.groups.yahoo.com/group/OpenCV/message/79758

But it looks rather time-consuming and there are also people complaining about more problems with this solution:
http://stackoverflow.com/questions/5869397/opencv-ubuntu-11-04

So i think we should wait for an official bug fix from OpenCV.

@Thomas: could you talk with Sascha about how to link a different system OpenCV version to the dart client.

Peter is working on it.