NULL pointer problem

[Bladeblade]

The problem is at return insert(cap->drt,x,poz--);
(*cap).data CXX0030: Error: expression cannot be evaluated
cap is the head of a double linked list.
It works for the afisare function (cap=cap->drt;) but crashes at insert
Both functions get the same pointer transmitted

void afisare(Element *cap)
{
while(cap)
	{
		cout<<cap->data;
		cout<<" -> ";
		cap=cap->drt;	
	
	}
}

Element insert(Element *cap,Element *x,int poz)
{
if(poz==0)
	{
		cap->drt->stg=x;
		cap->stg->drt=x;
		x->drt=cap;
		x->stg=cap;
		exit(0);
	}
else
{
	return insert(cap->drt,x,poz--);
}
}

If needed i can send the whole project.

Tank you !