Found /shared/Public/twonky/resources was empty.
Hope the next version of Twonky fixes this !
copied contents from resources folder from unzipped install folder to the NAS folder above
You can log into the NAS with Windows Vista by right clicking on an open 'My Computer' window and adding a share by adding a network location (with the ip address of the NAS) ie: 192.168.1.5/share
Now http://192.168.1.5:9000/config brings up the missing webpage configuration and as a side note once I set up the shares and settings under config my DLNA Error (7531) is no longer showing on my PS3.
Now streams most files perfectly.