There are differences between the instruction for installing Flowscan with Flow-Tools on http://www.scd.ucar.edu/nets/projects/completed/2001.complete.projects/netflow/netflowdoc.html and http://net.doit.wisc.edu/~plonka/FlowScan/INSTALL.html#Software_Upgrade_Requirements The second says it its necessary arts++ and the first not. Any help appreciated.