Multicast not working through trunk ports

Hello,

We have set up a small network consisting of 4 netgear GS724T, 4 GS724TPS and 3 Netgear S3300.

We have a DNS multicast service running on  a client which is connected to one of the netgear S3300, if we plug a client directly into the same switch that the DNS service is running on, the client successfully registers to it.

However if we plug the client into one of the other switches, that are trunked with the original switch,  it will not successfully register with the DNS. It seems as though it will not pass through the trunk ports. The network connectivity is there as they are on the same VLAN and they can ping each other.

We have all the IGMP snooping services turned off so this should not be a problem.

Is there a potential configuration error that we may have to edit that will help with tagging on multicast ? 

This is all network connectivity within the same VLAN the multicast does not need to go through to other VLANS, it is using vlan 40 and NOT vlan 1.

Any help would be much appreciated!