well... I've done the following:
clean install - debian net install - 7 (wheezy) 64-bit, xfce4 desktop, xfwm4 window manager.
at this point stencyl does not run.
then, after configuring multiach support, stencyl does run, but generates the invalid SWF file name error... because it never generates the file...
I noticed something in the log that makes me suspicious:
...
[LOG] Write String out as file to: /home/chris/mm.cfg
java.io.FileNotFoundException: /home/chris/.macromedia/Flash_Player/Logs/flashlog.txt (No such file or directory)
...
see attached log... thanks...