Back after hiatus; custom messages no longer work

A few years ago I started work on an adaptation of Robert Browning’s “My Last Duchess.” Life intervened, but last week I decided to take a new look at my work in progress, so I downloaded the latest version of Inform and opened my project file. Unfortunately, the new version of Inform has taken a dislike to my old source code.

Since the game takes the form of a dramatic dialogue (in the second person) I tweaked many of the default messages using the extension Default Messages by David Fisher, and that’s what’s throwing the error messages:

Here is a truncated list of what some of the customized messages used to look like in my source code:

Table of custom library messages (continued)
Message Id  	Message Text   
LibMsg <empty line>  	"At times I cannot think of anything"  
LibMsg <unknown object>  	"Sometimes my eyes, like yours, are drawn toward [line break] Inconsequential things better ignored."  
LibMsg <cannot go that way>  	"[if the player is the emissary][one of]My Duchess sometimes roamed where she should not ....
LibMsg <report player giving>	"I vouchsafe I will keep it under lock [line break]And key.[line break]"
LibMsg <confirm Quit>  	"[if the player is the duchess]I once posed her the selfsame question ... 
LibMsg <block asking>	"There is a time and place for everything.[line break]"
LibMsg <Inventory no possessions>  	"Your pockets are as empty as my soul.[line break]"    

Is there a new version of the extension that would fix this problem? Any help would be greatly appreciated.

That extension has been replaced by the new Responses system. Rather than editing a huge table of values, there’s a nicer syntax for editing the library messages that even allows them to change during play. See §14.10-14.11 in the manual for details.