Each new version of SEO PowerSuite tools undergoes stringent quality control so errors are quite rare. If you do come across one, please tell us about it as soon as you can. We'll do our best to help you solve it through software settings or issue a prompt fix if it turns out to be a bug.
Most errors can be avoided by simply keeping Rank Tracker up-to-date. Even if you don't use the tool very often, please open it once a week and let it update itself (full version history is available here). If your version is several months old, it would be best to reinstall the application.
Rank Tracker is equipped with advanced task logging functionality. It lets you easily share information about errors with developers.
Open a terminal emulator and run a command to get the list of Java processes that are currently active.
ps -ef | grep java
Now you need to terminate the process associated with Rank Tracker. This is done through the following command:
kill -s KILL {pid#}
{pid#} is to be replaced with the actual process ID that appears right next to your user name (highlighted on the screenshot).