Hi,
How did you open rtmpdump? It looks like you double clicked the icon or used command-O in Finder.
You should run rtmpdump in Terminal, something like:
Code:
cd ~/Desktop
rtmpdump -r rtmp://hostname/app/playpath -o output.flv
or
Code:
rtmpdump -r rtmp://hostname/app/playpath -o ~/Desktop/output.flv
You may also need to add -W for swfurl, -p for pageurl, and other options depending on host and/or flv you want to download.