RPG Maker and DLL's

So, I am wondering if we are actually allowed to 'enhance' RPG maker with self/other user created .dll's ?

For example...

I make dll called 'ABC.dll' - this dll is the most awesomest thing in the whole world! FACT!!

Lets say someone was to then make a game (commercial/not) using the 'ABC.dll', would this be against the EULA or TOS or some crap?

Is there certain things we are able to make dll's for that would be allowed, but some things that are not allowed?

Another example - the res breaker dll that was unearthed a while back (before the official one) was not able to be used commercially due to a breach of EULA or something ??  Why was this?

Basically, what are we allowed to make our dlls do before it beaches the EULA?

Am I allowed to make && use my dll to insert 'secret' methods into the engine?

Can I change how default classes function all together?

Some official info on this kinda thing would be alot of help :)

also - i felt this should have went in some RPG Ace forum, but didnt know which one, so if it needs moved I'm sorry for keeping you mods in a job ;)

my understanding is.. you can have dlls. It's only against the terms if you open the game's normal dlls and make edits to them. Hence why the resolution one was illegal.. because it modified one of the core files

from http://www.rpgmakerweb.com/support/information/eula

And yet an open sourced RPG Maker could really help to bring popularity back to the series.