One common issue with some Linux distributions, especially Ubuntu and other ones which make heavy use the sudo command, is that after installing PersonalBrain, the default option is for it to launch and then have you create a new Brain with it. What happens is that your new Brain is created under sudo permissions, which doesn't allow you to access it as a normal user. However, this can be easily fixed with a few simple commands!
Open up a terminal in whichever environment you're in. In most cases you will see the "bash" prompt, or whichever terminal shell you use. By default, your terminal should be in your home directory. If it isn't, type "cd" like this:
In this case, pretend we named our first Brain Yourbrain. We would type "echo YourBrain*" like the following:
bash-3.1$ echo Yourbrain*
Now that we're sure our first Brain "Yourbrain" is in the directory we can continue on. Assuming the username is "yourname", we can go ahead and type "sudo chown yourname Yourbrain.brain" and "sudo chown -R yourname Yourbrain_brain/" as follows:
bash-3.1$ sudo chown yourname Yourbrain.brain
bash-3.1$ sudo chown -R yourname Yourbrain_brain/
Afterwards, everything should work perfectly. Boot up PersonalBrain and have fun!