Everytime I try abjusting my video settings to maximum I close the window, open it again and my settings are reverted... Is this caused by streamline? How do I fix this?
Did you even read the streamline readme?
One of the feature of streamline is to manipulate the settings so that your fps falls into the range specified in the ini...
So yes it will change them...
edit:
You can also change that behavior by desactivating the feature in the ini file.