Shared Folder Access - VPN and Server 2008R2

I have 2 domains in 2 different locations. I have a VPn connection from my ISP between the 2. I also have 2 different ip ranges for each domain. I can ping domain A range ( 192.168.2.1) from B ( 192.168.1.1) and vica versa. Furthermore, if i want to connect to a shared folder on domain B ( \\192.168.1.1 ) i get access. If i want to access a shared folder on Domain A ( 192.168.2.1 ) it cannot access it. I can ping the 192.168.2.1 adress, but not access the shared folder. Is is a security feature in Server 2008 that i am overlooking ( the shared folder is on my domain controller which is 192.168.2.1 ) If i set up a shared folder on any other machine on my 192.168.2.xxx domain, i can get access from the B domain. Furthermore, i cannot resolve pc names on my Domain A ( 192.168.2.1 ), i take it because its a vpn connection and DNS wont resolve across 2 networks? What am i missing to enable a shared resource on my server 2008 DC?

Please assist.