Like Samet says, your heap space is probably still set to the minimum of 64 MB and this might just be the thing that tipped it over in terms of size of the application model. I would expect other additions to the model to result in the same thing. It looks like it just barely still loaded the model, but when you actually start doing requests it becomes too much. That said, the actual request that caused this error is when it's loading a bundle to translate something in your model, so it's not directly linked to the index itself.
I also recommend upgrading to version 4.6.0 by the way, but at least definitely to the latest patch release, i.e. 4.5.2.
Hi Robin, could you increase your Java heap space? It seems that the available momory is just not enough to add the index to your table in the database.
You can do that in your project settings.