What does "mds: (Error) Volume: Could not find requested backup type:2 for volume " signify?
I have only seen that in relation to Time Machine timing out when preparing a network sparse disk image for backup.(and I've seen it on Snow Leopard and rarely on Lion - but lion is young)

mds is very tightly intertwined in the time machine process, so it could just be time machine asking mds to do some work. 

You'll have to disable time machine and watch for other network mounts failing - separate the two and you'll have narrowed it down to one bad actor.