Thematic mapping also working now Dominique, it was our mistake, some layer id mis-match.
However, if ESRI is interested in feedback, I would like to suggest that when free samples are given and then when code changes due to upgrades / other reasons, it would be good if ESRI posted updated sample codes, otherwise like us, we could be stranded in a situation where a functionality worked in an earlier version but now does not in a newer version.
Thanks for all your help.