It could be possible that I have some random trigger that may be stopping it, but I have a very similar trigger to this one that works just fine...
I doubt you'll find anything, but here:
Trigger("Player 1"){
Conditions:
Bring("Player 1", "Vespene Orb (Protoss Type 1)", "Player 1 ", At least, 1);
Switch("Player 1 Attack ", set);
Deaths("Player 1", "Protoss Unused type 1", At least, 1);
Deaths("Player 1", "Terran Science Facility", Exactly, 1);
Deaths("Player 1", "Zerg Lurker Egg", Exactly, 0);
Actions:
Set Deaths("Player 1", "Terran Science Facility", Subtract, 1);
Create Unit("Player 1", "Zergling", 4, "P1 TF");
Set Deaths("Player 1", "Zerg Lurker Egg", Add, 5);
Set Deaths("Player 1", "Mineral Field (Type 3)", Subtract, 1);
Create Unit("Player 1", "SCV", 2, "P1 TF");
Preserve Trigger();
Comment("TF");
}
//-----------------------------------------------------------------//
None.