Dial-up access causes the ISP to assign a public IP address from a pool to
your system just dialed-in. To get ICS running, you need a NIC in the same machine
AND to create an IP address for it --
this usually becomes 192.168.0.1 automatically by enabling ICS.
Sadly, a router frequently wants to use this address also for itself.
To make it work, change the router's address to 192.168.0.240 and
set the WAN gateway to 192.168.0.1. Let the router perform DHCP for
all devices attached to it.
All systems should be able to ping one another as well as your ISP.
File/print sharing would also be possible, BUT THINK TWICE because
you're on a public IP address and your firewall is all there is between
you and the bad guys.