Can't autofilter my spreadsheet!

hello, I've spent quite a long time gathering this data, and I'm nearly finished, but all of a sudden I can't use autofilters (or many other options on the toolbar(s).) It says [Group] at the top, and it seems like that's new.

(sorry about my noobness, but I'm getting better week by week.)

-Mikael

Ah, and I'm using Excel 2002 (XP)

Also, the file is too big to attach here (505k compressed) so It's hosted here:
http://www.mediafire.com/?cdxzyzdtrdx

It appears that you have selected more than one sheet at a time (likely pressing CTRL while selecting the sheets). To undo this, right click on the sheet names, and select ungroup.

thanks much :-D