There are a few things that could be wrong here.
1. The samba share you have set up is set to deny access to whatever machine or account you are using to access it.
2. The firewall on the Linux server is blocking samba ports.
3. TCP Wrappers is blocking the samba application.
4. Samba hasn’t been started.
Best way to start diagnosing the problem is to try to log onto your share locally on the server with “smbclient”.