Possible causes of "TypeError: $dataMap is null"?

Hey rpg maker forum, I released my web game made in rpg maker mv almost a week ago now, I have been able to fix almost all of the bugs users were having other than a random crash some users have when moving from one room to another that crash is "TypeError: $dataMap is null", I have not been able to find the cause of this or been able to reproduce it myself so its been a pain trying to fix :p

Any one know what the possible causes of this are?

Here is a link to my game if any one wants to try reproduce the bug but I have had no luck in doing so
http://www.newgrounds.com/portal/view/692782

Here is a link to someone who actually has the bug while lets playing
[embedded media]

If you notice she gets the error as she is about to be moved to a seperate room, however she then replays the game and does not receive the error, so its not 100% reproducible by the looks of things.

Also this bug does not happen at any single point, I have had it being reported happening at other parts where you are moved form one room to another.

My game is running the following plugins in the following order:
TDDP Preloader Manager
SRD Skip Title Screen
Yanfly Core Engine
TDDP Bind Picture To Map

I can not reproduce the bug when running with and without plugins enabled, I really just want to know what are the possible causes of this error, thanks.

If any other info would help then let me know and I will try get it asap.

That error means that some code was executed while the map was still being loaded.
I ran your game and set chrome to simulate a very slow connection and got a similar error on the TDDP Bind Picture To Map plugin:

Datamap is the structure that contains all map data. If that is null, then that means that the engine has no map loaded when it tries to access that data.

could be a problem with the preloader plugin, or could be damaged mapfiles, or could be that the directory path to the mapfile has a problem.
If it works sometimes and other times not it would point to a timing problem with the preloader, that sometimes the engine is allowed to continue before the preloader completed loading of the mapfiles (the risc for this would be higher with larger maps than with small maps)

So removing the preloader plugin might help you think?
Was thinking of doing this and just using smaller images to allow the game to load them faster and remove the need of the preloader plugin.

Thanks for the help :)