RxJS-DOM - Cannot read property 'AbstractObserver' of undefined

I've just included RxJS 5.4.0 and RxJS-DOM 7.0.3 on a page and got this error in the console:

TypeError: Cannot read property 'AbstractObserver' of undefined

How can I resolve this error?

Rx-DOM is not fully compatible will RxJS 5.

See open tickets on github:

• https://github.com/ReactiveX/rxjs/issues/1223
• https://github.com/Reactive-Extensions/RxJS-DOM/issues/105

To avoid this error you need to use RxJS 4.