[Asterisk-Users] Unable to create channel of type 'IAX2'

[Wilson Pickett]

> Where is the mistake?

Right here

> [local]
> exten => _XXXXXXXXXX,1,Dial(IAX2/${EXTEN})

You are telling it to dial ALL 10 digit numbers using IAX. What you
need to do is have an extension that determines if a call is meany for
the X100P and if so the dial would be

> exten => _XXXXXXXXXX,1,Dial(ZAP/1/${EXTEN})

ZAP/1 is your X100p FXO.

Take a good look at http://www.asteriskdocs.org which was entirely
written to help you understand channels, extensions and dialplans.
These are the essential building blocks to get you going.
 
You will need further knowledge to separate internal extensions from
external phone numbers. Often internal extensions are numbered like
2000,2001,2002...

example 
> exten => _2XXX,1,Dial(IAX2/${EXTEN}) ; hand all 4 digit numbers that begin with 2