Power Point Frustrations

So I went to the Brooklyn Botanic Gardens today to give a 6-hour comprehensive presentation all about tropical plants -- and then, it happened -- that nightmare event that so far I had only dreamed about and feared -- my power point files didn't open!! I had saved the slide shows as .ppt files on my Apple computer and then burned them onto a disc -- when I then tried to open them on the garden's IBM lap-tops, the CD-ROM icon showed up, along with the file folder called "Presentations," but when I clicked on the file folder to get to the files, a message came up saying "Folder is empty" ... so I tried opening Power Point and then opening the files from within the program and got the message "Unable to access files ..."

I thought I had made a mistake in burning the CD ... but when I got home, I was able to open the disc and open the files on my computer --- does anyone know what went wrong??? Please help!!