Hi Erik, thanks for the quick reply. I'm afraid it doesn't solve the problem though... I checked /etc/ld.so.conf, and the line you specify was already there. The directory it points to exists, liblvrt.so.6.1 is in it. Running ldconfig poses no problems either... What surprises me most is that the app does run from a shell command. Also if this shell command is given from within the C-program, for instance with system(), or by calling a script file that calls the app...
