Need a newer version of Page to open document
I couldn't be more frustrated with Apple right now. I installed iworks 09 from a disk. I bought it on Amazon. I wrote a document with it yesterday. Today I can't open it. It says that I need a newer version of Page to open it. It instructs me to go to the Apple Store and upgrade. When I go there won't allow me to update because I have the Lion operating system. I've already installed Maverick and it was so problematic I reinstalled Lion. Why can't I open a document I just wrote using the version I bought? Any ideas? Thank you!
MacBook Pro (15-inch Mid 2012), OS X Mavericks (10.9)