Problem with accessing nodes on both sides of VPN tunnel

[bugman]

Here is the scheme of connecting 2 networks over internet with using WinGate VPN. PC4 successfully connects to IP a.b.c.d, router transmit incoming traffic on UDP/TCP 809 to local machine (port mapping) .... blah-blah-blah.... finnaly connection is establishing.

The problem is:
When connection is established, PC1-PC3 can ping PC4-PC6, but only PC1 can access to services of only PC4 (WEB, RemoteDesctop, Telnet, Ftp, File Sharing).
From other side of VPN connection, PC4-PC6 can ping PC1-PC3, but only PC4 can access to all the resources of PC1-PC3 (RemoteDesktop, File Sharing, WEB server)

What is needed:
Every PC must access to all services of other PCs

Notices:
As it can be seen from picture - PC1 and PC4 with WinGate VPN installed are not the default gateways in their networks - so i've installed Rip2Client on every PC in network (even on PC1 and PC4). Drivers on PC1 and PC4 are updated. All firewalls are turned off.

[jamesc]

so i've installed Rip2Client on every PC in network (even on PC1 and PC4).

PC1 and PC4, which run the WinGate VPN software, should not have the RIP2 client running on them; it is built into the software.

Can you please remove and advise any new feedback.

[bugman]

I've stoped and removed service from PC1 and PC4. The probem remains with the same symptoms