Came across this error message last week when compiling in the Flash IDE
“The linkage identifier ‘BottomRightBetButtonSymbol’ was already assigned to the symbol ‘BottomRightBetButtonSymbol’, and cannot be assigned”
You’d think I had more than one item in the library with the same linkage ID, but it was in fact caused by a MovieClip symbol with said ID being used as a movieclip instance in one place in the movie and as a button instance somewhere else (an unused frame). Thanks to user “marleeffh” for posting about it here. Fair enough, this was bad authoring on my part, but the error message was a bit of a red herring.