Lion not responding to mouse clicks over VNC
This is a very popular issue. VNC server is not the only thing that has problem working with Lion.

I think the problem stems from the fact that; Lion can handle multiple user connections. So to make it work, you need to logout of your Mac first then try connecting remotely. More information in this forum..

http://forums.macrumors.com/archive/index.php/t-1193137.html