I am stuck please help (mysql)

Hello i got the 4th edition of building your own database driven website using php and mysql and i have a the flowing problem.

Linux Installation(On page 34 i have to create a link ) by doing the folowing
root@machine:/usr/local# ln -s mysql-version-linux-platform mysql
i replace the version and everything the link is created, but when i go to the next part which is changing directory into the link it tells me what the directory dosn’t exist

i am ruining ubuntu 9.10

this is actual copy and paste of the error i am getting

root@John:/usr/local# ln -s mysql-5.1.45-linux-i686 mysql
root@John:/usr/local# cd mysql
bash: cd: mysql: No such file or directory
root@John:/usr/local# ls
bin games lib mysql sbin src
etc include man mysql-5.1.45-linux-i686-glibc23 share