Global spells incompatible qith each other?

[Viajero]

I just cast Fata Morgana in a MP game... no other fata Morgana is up. SHould have been easy. No way, the message says it was not successfull because it was "overpowered by the current existing global spell and did not take effect"

WTF! there are only 4 globals up and none of them is Fata Morgana. Anyone has an explanation or this happened to them before? only thing I can think of is that Fata Morgana is incompatible with "Gift of Nature s Bounty" which has a similar effect and is one of the 4 globals up in my game?

I dont really want to try again and loose the gems uselessly... Any ideas?