Maximum execution time of 300 seconds exceeded error while importing large MySQL database

It seems to me that your .sql file actually contains the text <br /> <b>Fatal error</b>: Maximum execution time of 300 seconds exceeded in <b, which is obviously not valid sql. You have possibly exported your database with some tool like phpMyAdmin, which took longer than 300s to create the export which was cut short at that point in time.

This is a syntax error in the .sql file. There should be a line there with "<b>Fatal error: Maximum execution time of 300 seconds exceeded in

This error looks alot like a PHP error to me. During database export/dump, php stopped after 300 seconds, and wrote out the error to its output -> your file.

You should fix php.ini, to allow longer execution time, then export the whole database to a new file, and then import the new file (I guess the database was exported via PHP ofcourse). Or use some other tool to dump the databse (like mysqldump, or mysql-workbench if your prefer a GUI), and import that.