im in a class at school for webdesign. we have flash on only our apple laptops,
which have OS X, and our pc's have XP. i want to be able to work on the .fla at
home when im out of class. but when i load it on my computer, it says
"unexpected format" and doesn't open it up.

is there something that i can do so that i can fix this? help would be greatly
appreciated

There shouldn't be a problem with opening a .FLA file using different
platforms. However, the problem could be caused because the Apple Laptops have
a newer version of Flash then your PC. So, open Flash on your PC. On the title
bar, it should say what version of Flash you are using. Like, Macromedia Flash
MX 2004, Macromedia Flash MX, or something of that sort. Now, when you use the
Apple Laptops, open the Flash file, and go to File > Save. Now in the File Type
drop down list, select the version of Flash you use. Now save. Open this
version of the FLA file on your PC.

You will probably also have some problems with fonts. (If you use them.) If you
don't muck with them, it should be fine when it comes back to whichever
platform you started with. There is no way to embed fonts in the fla only in
swfs.

Make sure you fla actually has a .fla suffix - ie Flash on a Mac will save
you file as:

myFileName

whereas a PC expects it to be called

myFileName.fla