It seems that after unzip your config files was overwritten to defaults one.
Check your system/coreinfo.php if it's not empty and contains path to seotoaster core and sitename ("application" by default). Also seotoaster_core/application/configs/%sitename%.ini (%sitename% should match one from coreinfo.php) if it contains proper database settings, website url and website path.
You can also reinstall via installer - but you will loose all changes you made on toaster before upgrade to 2.0.2, because installer requires clean database. (There is a trick also: create new clean database, install toaster to it, then change in %sitename%.ini database name to previous one that you installed 2.0)
Feel free to send us your config files or error log messages if you will have any troubles.