Wow you were lucky! Yeah as mentioned I don't like the LW 5 function of auto-deleting the incomplete files if cancelled accidentally or deliberately. There should be a popup window asking 'Do you wish to remove/delete the incomplete file?' in the same way as if you were deleting a file from the Library it comes up with a popup window with a question & multiple choice option.

But then there is no way to resume incomplete files in LW 5 at this stage. Only option would be to revert to LW 4 & resume it then go back to LW 5. lol It does happen to some people that their LW crashes & refuses to resume the incomplete files. Reverting to LW 4 works in that scenario since it does have a Resume option.