We have a CCM 4.x in our lab, change site and the MOH of telephony stop of the play. I restart de TFTP and MOH Server but nothing!
We are using CISCO2801 like MGCP gateway.
MoH by default does not support G729, but you can configure CallManager such that it can stream G.729 as well. To do this you need to go to Service Parameters for Ip Voice Media Streaming Application and for the field "Supported MOH Codecs ", check G729 along with G711.
Hope this helps