I've read from the F&Q that Jcow installed in localhost will have problems sending & receiving emails and in my case it's true. I cant send invitation and cant receive email notifications. Is there any solution to this problem?

I think you better use phpmailer to replace it.

Do you have any idea how to do it?

I can show you later after I figured out what happened to my problems and decided to use this script. Currently I am still evaluating this script.

You can download phpmailer from here:

http://sourceforge.net/projects/phpmailer/

You can google examples and there are many.

You can use a gmail account if you don't have your own email account that can send smtp mail.
This JCOW community sends out email using hostmonster.com smtp server. Apparently, it is using mail function though I don't have time to check it yet.

set any free mail server at your pc and will do the trick if you are 24/7 online