vray camera from exr (not working)

import nuke

def createExrCamVray( node ):

    mDat = node.metadata()
    reqFields = ['exr/camera%s' % i for i in ('FocalLength', 'Aperture', 'Transform')]
    if not set( reqFields ).issubset( mDat ):
        print 'no metdata for camera found'
        return

    first = node.firstFrame()
    last = node.lastFrame()
    ret = nuke.getFramesAndViews( 'Create Camera from Metadata', '%s-%s' %( first, last )  )
    fRange = nuke.FrameRange( ret[0] )

    cam = nuke.createNode( 'Camera2' )
    cam['useMatrix'].setValue( False )

    for k in ( 'focal', 'haperture', 'translate', 'rotate'):
        cam[k].setAnimated()

    task = nuke.ProgressTask( 'Baking camera from meta data in %s' % node.name() )

    for curTask, frame in enumerate( fRange ):
        if task.isCancelled():
            break
        task.setMessage( 'processing frame %s' % frame )

        val = node.metadata( 'exr/cameraFocalLength')



        cam['focal'].setValueAt(float(val),frame)

        val = node.metadata( 'exr/cameraAperture')
        tx = node.metadata('exr/cameraTransform')[12]
        tx = node.metadata('exr/cameraTransform')[13]
        tx = node.metadata('exr/cameraTransform')[14]

        cam['haperture'].setValueAt(float(val),frame)
        cam['translate'].setValueAt(float(tx),frame,0)
        cam['translate'].setValueAt(float(tx),frame,1)
        cam['translate'].setValueAt(float(tx),frame,2)

        # CONVERT STRING BACK TO LIST OBJECT AND ASSIGN
        matrixList = node.metadata('exr/cameraTransform')
        #for i, v in enumerate( matrixList ):
        #    cam[ 'matrix' ].setValueAt( v, frame, i)
        # UPDATE PROGRESS BAR
        task.setProgress( int( float(curTask) / fRange.frames() *100) )