I'm trying to input a short singing part (with lyrics) into a battery score, but Sibelius crashes every time I do.

I'm running Windows XP, using Sibelius 5.2.5 and VDL 2.5.2, and my playback setting for this score just has one instance of Kontakt player 2 loaded and set to use the VDL soundsets.

I've created a typical battery score using the VDL template. For a short phrase, I've inserted an instrument change to ";voice"; and a change back to SnareLine Manual afterward. I'm able to input the melody just fine and when I do, Kontakt player automatically loads a Piano sound set to play back the pitches, which is fine because I don't care if it actually plays back as a voice. When I click on the notes I entered, the piano sound plays back just fine. Then I start entering the lyrics (using Ctrl + L). The lyrics enter just as expected, but once I've finished typing them in and click elsewhere on the page, Sibelius immediately crashes and closes. Then when I re-open Sibelius and try to re-open the file I was working on via the ";recent files"; drop-down, I get an error saying Sibelius can't find the file.

Any idea what could be causing the problem?