Hello,
That error usually occurs when the workspace file (in this case, the default workspace, "two_agents.sim") can't be located. Simbrain stores the last open workspace file as a
user preference, so that when you start Simbrain the last workspace you worked with is automatically loaded. So, you can get rid of the error simply by opening a new workspace file. To do this, just go to File > Open Workspace, and navigate to the "sims" folder, in your case /home/[userfolder]/../Simbrain2/simulations/sims and open a workspace file. two_agents.sim is in simulations/sims/vehicles.
After you open it, next time you reopen Simbrain it should automatically load that workspace file.
Tell me if this works. If not, it may be something else specific to Ubuntu (I have not tested Simbrain on Ubuntu), which I can look into.
- Jeff
