[CentOS] what's the ftp password?

Hi all:
 i installed php, apache, mysql on my CentOS.
 then i installed wordpress on localhost.
 when i upgraded a plugin, wordpress asked me to enter "hostname",
"username" and "password".
what's them? i tried mysql username and password, they didn't work.
 anyone can help me? thanks so much.

-- 



                      Yours JudahXIII