Just did another test...
Opened the MIDI file in Anvil Studio (btw, its freeware).. Stripped out the text fill into track 19's copywright box... Then said "export as General Midi Type 0"
I sent the file to the phone, it got there.. and it played and allowed me to apply as ringer.
So it appears that it was either the copywright text, OR the fact that it was a General Midi Type 1.