VPN connection windows8 SBS2013

Is it actually a "VPN connection from a windows8 client to SBS2013" or a VPN connection to the CheckPoint appliance?  i.e. is the Checkpoint unit the VPN server or the SBS?

Try on the connecting client, from a command prompt with elevated privileges, adding a route as a test:
route add  192.222.33.0  mask  255.255.255.0  192.222.254.xyz
assuming the SBS LAN is 192.168.33.0  and substitute the correct latst octet of the client's VPN IP for xyz.

To remove:
 route delete  192.222.33.0

You also need a return route but presumably the CheckPoint is the  default gateway for all machines on that LAN, which will take care of that.

This is not a good long term solution as the VPN client IP will change, but if successful we can go from there.

Software firewalls on all device may block abscess as well, as generally the firewall exceptions are for local LAN access only.  Ping is often allowed , use it as a test, or try disabling software firewalls on the devices to which you want to connect.

ps- SBS 2013?  A typo?  I assume 2003?

1. It is SBS2010
2. The connection is going through the Checkpoint unit but I believe the VPN server is actually the SBS
3. I have tried the Route add but the problem still exists.
4. It looks like the problem occurs only when I try to connect a non-domain computer from within the LAN.  The client is connected inside the office through WIFI with on a separate sub-domain (for visitors).  When I make the VPN connection from outside the office everything seems to be working properly, with the VPN connection getting the right I.P. address.

>>"The client is connected inside the office through WIFI with on a separate sub-domain "
This sounds like a different network segment.  Many WiFi routers create a visitor network that is isolated an unreachable form the corporate LAN intentionally for security reasons.  If thisis the case they are not going to be accessible.

Are there devices on the wired SBS LAN to which you can connect?

Can you elaborate on the network configuration, as per the following questions?

 >>"I believe the VPN server is actually the SBS"
You need to confirm this as it makes a difference.

Does the SBS have 1 or 2 NIC's, and what are their IP's?

>>"The VPN connection gets an IP address on a different subnet than the LAN. "
Though this is quite acceptable it is not a default SBS configuration  (unless ISA, see below).  Did you create the VPN with the SBS wizard in the Server management console (as should be done) or within the RRAS console?

Is ISA installed on the SBS  (i.e. SBS premium with ISA)?

Can a WiFi client ping the SBS?

I have found that when I set up the VPN to use certificate for L2TP connection, everything works as expected.  If I set the advanced to connect using a pre-shared key the connection get assigned the different I.P. subnet.
I think that with the pre-shared key, the checkpoint appliance acts as the VPN server and when the certificate is used the SBS acts as the VPN server