In my last post  I wrote that there is a new aghost.js you need. The main reason is that the December CTP of the WPF/E plugin  is only running until end of January, so you have to update your plugin with the February version . If you have installed the old version you will get following error message:
Once you have clicked on ok you will only see an empty placeholder. If you switch to a new web site including the WPF/E plugin it will not display the error message again.
But, you may notice that the size of the message box is different to the size you want to use for the WPF/E plugin. To do this I simply changed the aghost.js  to add the correct width and height you have specified while creating the container.
So, if you have a WPF/E plugin written that has to fit in the whole page layout you may want to change this.