I've found that a few very old projects of mine don't load in SPLAT, so I've got Sonar 8.5 and Pro Audio 9 installed for that reason.
Most things load with no issues in 8.5, and once re-saved in 8.5 format will open up without issue in SPLAT.
In saying that, I've only got these installed on my Win 7 32 bit partition which I rarely need to look at nowadays.
V-Vocal was cool in the day, but I find Melodyne far superior.