Might help somebody out - I have an LG 620BP that I stream my media to and it plays everything perfectly except that I will lose the network connect to WD drive about every 20 mins or so. I have tried it on wired and wireless the same outcome. Set static ip address, the same. upgraded the twonkey, the same, turned off restart sever in twonky the same effect.
So its either the drvie or the LG player I am thinking, so I was looking through my router settings and notice theres a lease time in router for UPnp, so I decided to turn it off completely and not had a problem since on my Sagem router.
I dont know what affect or whether I should use my router without this setting, but seems to have solved my issue.