F-A-I-L what does that spell? but really, fire her.

(1) You're assistant would've known better if you'd only told him first. I'm assuming you didn't. (2) You don't use white boards as your only way of informational backup/provision. There's this incredible machine called a computer and a printer. Since you're apparently fluent enough to post an FML, it shouldn't be hard to grasp computer/printer use. In other words, if it's not YDI for the first, it's already a definite YDI for the latter. If you took care of the first, at least it isn't solely your butt on the line; in that case, drag the assistant down with you. However, a note of caution might be to take the primary blame yourself (plenty of it is still your fault) unless you want to look like a self-righteous prick.

way to go 92 way to goooo.....

I have a few comments here. First of all, no one ever writes anything worth keeping on an erasable board. There is a reason why they are so easy to erase, they are for temporary use. Second, you should have used a computer if one was available to you. I don't know about Microsoft project, but excel works for almost any situation. Third, just because it took you 10 hours to figure out the first time doesn't mean it should take another 10 to recreate it. If you used any kind of rational thought during the process you should be able to remember your rational decisions and rewrite them. It should take an hour, tops. If you know why you decided what you did it should be fresh in your mind. Postponing your meeting for an hour would hardly ruffle any feathers, especially if it was as important as you say. And finally, fourth, if you have an assistant, you should be important enough, or smart enough to make sure that they are up to speed on what you know so that they are aware of what you are doing, or could even make judgment calls in your absence. They aren't just there for your amusement, you should be teaching them something.

way to let us know 97 way to go

For something that I have spend 10 hours on, I'll be sure I have copied it down one way or another..

What a lot of great advice for the OP here. I hope she's learned from the comments if not from the experience. If it's not already clear, let's see: 1. Whiteboards are for temporary work that can be erased without a moment's notice (see recent experience). 2. Use something more permanent to capture the work of many hours - (insert favourite Microsoft technology here) or even use permanent markers on flipcharts. Anything but whiteboards. I wonder how the meeting went? Whose job is most at risk? The administrator who made sure the white boards were clean before a big meeting or the presenter who failed to make a permanent copy of her work?

It's kinda funny that so many people cry she should use a computer, get on with the times, etc... It's kinda funny too that the companies I work and worked for never used a computer-based system for work schedules or were switching from a computer based system to a...well..."outdated" one. And that aren't small companies...

I agree it sucks now the valuable lesson is next time leave a note not to erase the board without your consent ... probably that won't f*** up ur life that much ...

With the amount of technology resources and collaborative tools available, there is no reason to be doing this on a white board. Seriously.