Whs 2011 Networking Via 2 Routers

Hello all I have a slight problem with networking my WHS from my 2nd router.
Set up as I have now

Router A
Server connected
Modem connected

Router B connected to router A via homeplug
I cannot map a network drive from any of my pc's from this router and it does not show when trying to map the network.

I’m not too sure I have turned off DHCP on router B and still noting also assigning a static ip address .

Any help where I am going wrong will provide more information if needed.

Thanks WiiUe