Access violation with VirtualBox 5.1 Beta 2

[GreenReaper]

An access violation occurs immediately when using this tool with VirtualBox 5.1 Beta 2.

VBoxHeadlessTray code appears to be calling an invalid function pointer. Most likely API structures have changed in a way which renders the tool incompatible.

Ideally this tool might detect this situation and provide some kind of unsupported warning in the event of future incompatible API changes, rather than just fall over. Maybe there's a version field it could check? (Could see this getting annoying if it did "work"; on the other hand this avoids silent corruption.)