In trying to research my theme related Fatal error, I am looking around and noticed that the Permissions on my ...Themes folders are 705 and the files are 644, with the contents of those folders like Default being 705 & 644 also, but downloaded Themes like GanderGreen2.1.2a being 777 for folders and 666 for files.
I thought almost everything was supposed to be Folder 755 and File 644?
I also see a setting_bak.php elsewhere with 600 Perms - that makes sense to me. For many other deviations I'm having trouble figuring out what if prudent, safe, and necessary.
755 and 644 are the appropriate settings. 705 is a little severe and may cause issues, depending on your other settings.
As for why 777/666... that's often how uploads through the managers end up... just go and recursively set 755/644
It's not normally too much of a worry, because smf is very good about protecting access