(I know I already posted about this on the relevant bug report topic, and in the main release topic, but I don't know if people might be not really paying attention to those, so this topic is to try and get as many people's attention as possible.)
Apjjm has discovered a very serious bug in Flexi Toolkit V1.15; I have confirmed the bug also occurs in V1.14, but not any earlier version; V1.11 and earlier don't have the function the bug relates to; and while V1.12 and V1.13 do have the function in question, they don't have the associated bug.
The bug is triggered when the "Move To Next Rank" or "Move To Previous Rank" button is used on any level in Flexi V1.14 or V1.15. This doesn't immediately cause the problem, but rather sets a "time bomb" of sorts - when you save the pack (or try to build an NXP of it), the bug strikes, and most of your pack's data files get deleted.
Ideally, get the V1.16 update here:
http://www.neolemmix.com/old/FlexiTool.zipIf you are using V1.14 or V1.15, do not use the "Move To Next Rank" or "Move To Previous Rank" buttons on the Levels tab. If you are using a version older than V1.14 (or if you're using the newly-released V1.16), you do not need to worry about this.
There is no way to recover the data in this case, unless you have a backup of it elsewhere.
In this case, your data can be recovered. You need to go to the levels tab, and find all levels that you've moved to different ranks. For each such level, double-click it in the list, and in the empty "Filename" field in the dialog that pops up, give them a filename of some kind. If you do this for every affected level, you will be able to save the pack without issues.
