Alright, at this point, I think I understand what you are trying to do.
There are almost three levels. The first is the main power supply, which allows the towers to activate. The towers then send out the SCV reparibots, feeding them energy as they heal.
Once again, not sure what has said in previous posts, but I think that I can give a basic overview of what has been said. Tell me if I am wrong...
1) The main power souce is given a search behavior, searching for all repair towers in its radius. If it finds any, it applies a behavior to the tower, enabling it to send out the SCV's.
2) The tower has a search behavior as well, searching for friendly, damaged units that need to be healed.
3) If it finds any, it will send out an SCV from its magazine, with the command set to heal.
4) When the SCV is released, the tower that sent it applies a persistant that will periodically check if the SCV has less than full energy, and if the tower has energy to give. If it does, it will give the SCV energy.
5) When there are no targets, the SCV returns and the persistant is destroyed.
Is that pretty much what you are saying?
(Also, I'm pretty sure that the SCV's are refered to as the casters, the unit they are sent to heal is the target, and the tower that sent the SCV's are the source. I am pretty sure about that, not sure if that has been said, but I figured that is pretty important information that can be confusing)
I get it to find the factory even with filters, tested with the kill command. This time i made a dummy damage effect that the repairbot cast on the repairstation. The repairstation has a behavior that is supposed to respond to dummy damage but does not. I tried to change the location to defender and the Handled to Suicide effect. If it would respond to the dummy then i would have killed it self but its still standing. I made this only to test if it does respond.