Sorry, that’s not what I meant. I was asking if coldbox.system.web.loader.CFCApplicationLoader extends coldbox.system.web.loader.AbstractApplicationLoader.
That would mean that an instance of CFCApplicationLoader would be able to satisfy the requirement for an instance of AbstractApplicationLoader.
I just looked at the code that XMLApplicationLoader.cfc AND CFCApplicationLoader.cfc BOTH extend the AbstractApplicationLoader.cfc file. The LoaderService is designed to be able to accept an instance of either component. Since they both extend the abstract class, they should both be able to satisfy the requirement.
The reason you are not getting the error is quite possibly because you have the “Disable CFC Type Check” setting enabled. As far as why your host is erroring-- I don’t know. It’s possible your CF install is missing an update. (See Andrew’s question about what version of CF9 you are on)
For what it’s worth, you should request that your host enable the “Disable CFC Type Check” setting. I leave type checking on in development to help validate stuff as I code. On production, it’s commonplace to disable the type checking for performance (and since you should already know that the code works by then).