Yes, disable firewalls and AV's until you can successfully share/access.
In your ACL set the everyone group to full permissions.
You may want to "unshare" the folder then share it again with the everyone group set to full perm's....
To share... access the properties of the folder. Go to Sharing. Make sure its set to share this folder.
In the security tab you will find the ACL. Select the everyone group and set it to allow full permissions.