I got the same problem.
I used old Air Video for 2 years, and it still working very well what ever i have trouble with Air Video HD, on same computer.
For professional reasons, i have two internet connections at home, one on DSL and one with Cable TV (so two differents IP) One is connected to a Win7 32 Laptop (I7) and the other internet connection (Cable) is on Win7 64 Laptop (I7). All with latest version of VLC. Old Air video is working very well for 2 years on each systems/Providers).
Everytime i let Airvideo HD idle for a while (30mn to 1hour), on each laptops (so i have one client HD beta 1.0.7 on each system with different pincode), it always after idle, says it can't connect to the servers, any of them from my ipad (local, remote, 3g and Iphone (so yes, i have two servers listed in air video HD app in my ipad). None of them , what ever my internet provider are (DSL and Cable), and laptop, it just dont worked. When i check on both computers the "connection test", it says "Server is accesible from Internet", but got no succes in remote, even on local or 3G. At the same time, old air video still working very well on all of my systems/providers. So for sure, this is not my laptops and not even a problem from my connections. Because that would means both my routers and laptop have a problem, even Old air video is ok on them.
So only solution i found, is to quit client server HD, then re-start them every time the problem happens. The poblem showed first 30mn of use, then i used new 1.0.6 and 1.0.7 versions without any succes.
How can i help, what kind of infos do you need more to fix this ?