Using code shown below;

var i:int = 0;
var v:String = "ioc";

for(i=0; i<3; i++)
{
trace(i); //0-4 OK
trace(ioc.2.x = 100 // clip two moves OK
trace (v+i); //ioc1, ioc2,ioc3 etc OK

NOW, trying to move all clips(ioc1, ioc2, ioc3) on the stage at once, so I try...
v+i.x = 100; // I get error... Cannot assign to a non-reference value.
}