Dub and derelict-allegro5 "Could not find a valid dependency tree configuration"

[Mike Parker via Digitalmars-d-learn]

On Sunday, 10 April 2016 at 12:14:54 UTC, Pedro Lopes wrote:
> Hello,
> Every time I try to run a project with derelict-allegro5 
> package as a dependency, dub says:  "Could not find a valid 
> dependency tree configuration"
>
> I already cleaned the dub cache, that does not solve it,
> allegro package is installed (from alleg.sourceforge.net).
>
> dub works with derelict-SDL, etc.
>
> Thank you.

You say it happens when you try to "run" a project, but the error 
message sounds like it's happening before building even begins, 
correct? What platform are you on? What does your dub 
configuration look like? What does 'dub build -v' tell you?