This has been a problem with Fusion since version 1.0. My host OS has an openvpn connection that uses the tuntaposx network adapter, tap0. If the connection is up ahead of time, launching Fusion makes the openvpn connection go down. The terminal fills up with:
Sat Sep 8 11:39:42 2012 write to TUN/TAP : Input/output error (code=5)
Sat Sep 8 11:39:42 2012 write to TUN/TAP : Input/output error (code=5)
Sat Sep 8 11:39:42 2012 write to TUN/TAP : Input/output error (code=5)
Sat Sep 8 11:39:42 2012 write to TUN/TAP : Input/output error (code=5)
I need to re-establish the openvpn connection manually. Likewise, if the connection is up while Fusion is running, closing Fusion will result in the same error. It's not the launching of any particular VM that breaks the connection, it's just the launching or quitting of the VMware Fusion application that does it.
Has anybody else encountered this? Or better yet, is there a solution?