While trying to install the 5.0.18 RPM on FC3 (Fedora Core 3) I got this
error:
(SOLUTION BELOW)

warning: MySQL-server-5.0.18-0.glibc23.i386.rpm: V3 DSA signature: NOKEY,
key ID 5072e1f5
Preparing... ###########################################
[100%]
1:MySQL-server ###########################################
[100%]
060125 12:21:03 [ERROR] Can't create interrupt-thread (error 13, errno: 13)
Installation of system tables failed!

Examine the logs in /var/lib/mysql for more information.
You can also try to start the mysqld daemon with:
/usr/sbin/mysqld --skip-grant &
You can use the command line tool
/usr/bin/mysql to connect to the mysql
database and look at the grant tables:

shell> /usr/bin/mysql -u root mysql
mysql> show tables

Try 'mysqld --help' if you have problems with paths. Using --log
gives you a log in /var/lib/mysql that may be helpful.

The latest information about MySQL is available on the web at
[url]http://www.mysql.com[/url]
Please consult the MySQL manual section: 'Problems running
mysql_install_db',
and the manual section that describes problems on your OS.
Another information source is the MySQL email archive.
Please check all of the above before mailing us!
And if you do mail us, you MUST use the /usr/bin/mysqlbug script!
Starting MySQL...................................[FAILED]

---------------------------------------------------------------------------------------
Solution:
SELinux was blocking... something. To disable I used this:
/usr/sbin/setenforce 0
Then I re-ran the RPM install and it worked fine, to enable SELinux I used
/usr/sbin/setenforce 1

Hopefully this will help the next person with this problem.

-Cory