I suspect it is because you did not set your bridge up correctly.
All devices should be in the same address range, ie 192.168.0.xxx or 192.168.1.xxx not a mix of both.
Bridges a transparent devices. In other words you do not really need to give them an IP address. However if you need to connect to them for admin or in the case where the device hosts other services then they would need one.
Did you set a gateway address on the linux machine. It would be the IP address of the router.
And you will need to tell the linux machine where to do DNS resolution. Either the DNS address of your ISP or your router if it is capable.
If possible you should not use your xp machine as a bridge. It is not the best platform for doing this sort of stuff.