Roger,
I guess you do not need the Igmp access-groups at this time.I would also remove the static joins at least during testing to have clarity.
Create a packet capture on inside and outside, see if the IGMP packets are leaving from inside to outside.
"show pim neigh"
"show mroute"
"show mfib"
Would be also interesting.
If the IGMP is dropped for some reason, first of all check loggs (informational level) and ASP drops.
Maybe also consider using stub routing rather then PIM, it's simpler
http://www.cisco.com/en/US/docs/security/asa/asa82/configuration/guide/route_multicast.html