Ty,
I'm no expert, but I can only think of a couple of things.
To get the easy one out of the way first; is your hood release lever installed correctly inside the VX? I removed my dash (more than once actually) and forgot to screw the hood release lever back down properly. If it's not in their right, then it doesn't have anything to leverage against and the cable will be slack.
The only other thing that I can think of would be that the cable just stripped out of the lever or the latch itself (basically just came loose). Check both ends of the cable to see if there is a crimped, or cleaner area, of cable where it might have been cinched into the lever or the latch before.
On another note, please keep us (me) up do date on your Xenon install as I am VERY interested in doing the same mod.
Mark
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless