Fermilab-Tevatron. Measurement of the isolated photon cross section as in PBAR P collisions at a centre of mass energy of 1.96 TeV. The data come from a sample of luminosity 326 +- 21 pb-1 collected during the 2002-2004 Tevatron running periods. Differential cross sections are given for photon energies of 23 to 300 GeV averaged over the pseudorapidity range -0.9 to 0.9.. These are the corrected data from the erratum published in June 2006.