In your network places, there should be a name of a workgroup, and within that workgroup, you should be able to see the folder.
To make sure you are in the same workgroup:
right-click my computer>click properties>click the computer name tab>click the change button, and make sure that the workgroup name for both is the same.
If that doesnt work, post back, and we'll start troubleshooting the network itself.