Why are the following diagrams not equivalent?

Question

I have the following two diagrams:

@startuml
participant "__: Order Fulfilement Clerk__" as pOFC
participant "__: System__" as pS
oOFC -> pS : "1:getOrderNbr() : integer"
@enduml

@startuml
"__: Order Fulfilement Clerk__" -> "__: System__" : "1:getOrderNbr() : integer"
@enduml

The second one works correctly, the first one doesn't compile. What's wrong?

Comments

This is a UML 1.x diagram and not a UML 2.x diagram... just wanted to make sure you know that...

in UML 2.x Lifelines are not representing Instances but instead ConnectableElements in a model

Answer 1

Which version do you use? 

It works the same way if you use pOFC instead of oOFC

http://www.plantuml.com/plantuml/png/SoWkIImgAStDuIe0qfd9cGM9UIKAIl7nLWh-HIcfHGfkfJbfcJcfkQb0OUUSrABi-7WbXSHYXG9_DsTCFS6LnIMfkJ0bmLmWLGgwTa2cWfM2ag5LUce9s5Y_f28DJQ1GPbv9QdfgaHANGsfU2j0L0000