Have you gone into the security preferences and allowed for the other computer physical or virtual given allowance to the data to be shared?
If you want to make this easily mapped, allowing "everyone" access to a folder share is used, however its best to be specific to allowing only a certain user or computer to have allowance.
One other test would be with this system off the web, disable the firewalls and see if you can then establish a mapping to the share. If you can not with the firewalls both disabled, then you may have a problem with network config between them such as they do not have the same domain ( workgroup ). Its also best to use static IP addresses when using mappings as for using DHCP, the IP's can change and break it.
When creating mappings, I like to use \\192.168.1.102\sharedfolder$
In which if the IP address is 192.168.1.102 and the share is sharedfolder , I add a $ at the end of this share to hide the share. But while its hidden, it can be revealed pretty easily.
Other option is mappings to use \\systemname\sharedfolder$
So if the computer with the data share is called BobsComputer it would be like \\BobsComputer\sharedfolder$
