Hello,
In each version of LabVIEW you can only save to the previous version.
So in 7.1, you can save to 7.0 and so on. Of course assuming you and not using stuff that didn't exist in that version.
You can never open a vi save in a higher version.
So, to do that you must have all the in between versions installed.
I think the best thing you can do is post the vi's in this forum and someone will help you converting.
Paulo