Mantis is popular php based defect tracking application which works on top of RDBMS like MySQL and PostgreSQL. Recently I ported our Windows based Mantis installation to Linux. It used MySQL as backend. Here are the steps:
1. Export Mantis MySQL database from Windows, upload it on Linux and then import it to MySQL database on Linux. You can find detailed instructions for exporting and importing MySQL database here.

2. Upload the mantis directory to Linux. Use either ftp or Bitvise SFTP (recommended) to upload the files.

3. Modify config.inc.php to change the login and / or password as required.

4. Run the following:
yum -y install mysql-server mysql php-mysql php httpd

This will ensure that you have php, Apache httpd server, mysql server and required php libraries to connect to MySQL. In my installation I originally didn't have php-mysql library which was causing the whole thing to fail.

5. Restart httpd and mysql:
/sbin/service mysqld restart
/sbin/service httpd restart

You are done!