i wouldn't say that is problem, but you can edit embedded mst for your language and change "Please insert the disk: Mirror's Edge" in "Error" tablet to "Please insert the disk: [2]" so it then uses what you write in DiskPrompt column in "Media" tablet.
Same with LotR Conquest embedded mst's have "Please insert the disk: {[ProductName]}", changing that into "Please insert the disk: [2]" would use DiskPrompts in media tablet.
But like i said,i don't see any problem with it. Its not that hard to figure what disk yo need to insert
