if you see the following error it is because they are trying to activate the plugin while the OP theme is still activated....
Cannot redeclare akismet_fix() (previously declared in .../wp-content/themes/optimizePressTheme/lib/framework.php:868) in .../wp-content/plugins/optimizePressPlugin/lib/framework.php on line 832d
This problem is only happening because you are trying to activate the OptimizePress plugin while you still have your OptimizePress theme activated (if you notice in the error code it references both the optimizePressTheme and the optimizePressPlugin folders).
Please deactivate your theme prior to activating the plugin. They both do the same thing, but the plugin does not have blog settings since in WordPress, only themes can have control over the blog.
The theme and plugin can not be both activated at the same time.