Can't Bind for successful connection

I think your password for bindDN is wrong, The bindDn which you are specifying is cn=readonly,cn=users,dc=myorg,dc=com and the password using -W is empty. It may be wrong and it is unable to authenticate you before doing a search.

Try port 3268 instead, see http://technet.microsoft.com/en-us/library/cc978012.aspx for more information

This command works for me:

$ ldapsearch -x -LLL -H ldap://test.com:3268 -dbc=test,dc=com -D 'DOMAIN\username' -W name=username dn