I was right
Adding this host to subnet connection in ipsec.conf
left=192.168.0.2 # Local vitals
right=192.168.0.100 # Remote vitals
left=192.168.0.100 # Local vitals
right=192.168.0.2 # Remote vitals
allowed mylaptop to ping the zaurus connected to mymythtv.
It was a vpn issue after all. The reason why the zaurus could access the internet was because I had a host to subnet connection between mymythtv (host) and mylivingroom(subnet) in which the subnet was specified as 0.0.0.0/0. Indeed, connecting the zaurus cradle to mylivingroom would not have necessitated creation of additional connections since 192.168.129.0/24 would fall within the more general 0.0.0.0/0. To do the opposite, connect to the zaurus from elsewhere means that the subnets attached to mymythtv ( usb0 and company) need to be made accessible via a host(otherpc) to subnet(mymythtv) vpn tunnel.
I can see clearly now.
Thanks for your time and effort in assisting me to troubleshoot this.