Recieving I/O error while uploading photo, or Max Execute time error

Hello,

While trying to upload a photo in my media manager, I am recieving either an I/O error or this: "Fatal error: Maximum execution time of 30 seconds exceeded in /wp-includes/media.php on line 435"

I tried to edit the media.php file on line 435, but for some reason my code editor in my cpanel is being buggy and wont open up, therefore I cannot find line 435 to change the execute time. Would that fix the issue, or can it be resolved by another way?

Thank you for your help!

Luke