Private Share Acess

I am having some issues that some of my users are not able to access Private Shares that I have set up for them on the EX4.  They are attempting to map a network drive from their windows Machine but it won’t give them access.   I am not sure why I can do it on my machine, but they are not able to do it.  We are on a wired network.

Do they encounter a particular error message? What is the network configuration for those systems with regards to networking security?

Regards,