Two warning messages: one is about a mismatch, the other about headers already sent

Hello very helpful people,

I am following the text in the book entitled " Build Your Own Database Driven Web Site Using PHP & MySQL, 4th Edition by Kevin Yank. I’ve downloaded and installed PHP, MySQL, and Apache per this book. I’ve been performing the exercises and all has been working as advertised, until I got to Chapter 4 and started using myslqi. Now I get the two warning messages below. I’ve even downloaded the file for the book from Site Point and used those files for the addjoke lesson and I still get those two messages. Does anyone know what is causing this to happen??

Warning: mysqli_connect() [function.mysqli-connect]: Headers and client library minor version mismatch. Headers:50051 Library:50148 in E:\Program Files\Apache Software Foundation\Apache2.2\htdocs\addjoke\index.php on line 25

Warning: Cannot modify header information - headers already sent by (output started at E:\Program Files\Apache Software Foundation\Apache2.2\htdocs\addjoke\index.php:25) in E:\Program Files\Apache Software Foundation\Apache2.2\htdocs\addjoke\index.php on line 60

The headers already sent error is caused by the prior error message having been generated. Once you sort out the mysqli_connect error then the other error will disappear.