Resetting LDAP & MySQL Passwords
By far, one of the most common problems in getting a service started is an incorrect password.
Resetting the LDAP Password
Try running zmcontrol stop then ps auxww | grep slapd
Verify that ldap is stopped - if it's not, kill it by hand and restart.
If it still doesn't work
try shutting ldap down, then reset the password (both for root and zimbra) via:
zmldappasswd --root newpass
Make sure you use the same password for both!