My Flash MX 2004 Professional will not open older .fla files

I have a copy of flash MX 2004 Professional on my work computer but I’m having difficulties getting it to open some .fla files from flash MX (and flash 8). When I try to open the files I get the error message " unexpected file type." At first I thought it was because my files might be corrupt, I’ve been having troubles with my portable drive, but I decided to come here to Kirupa and download some source files and I got the same message so I think the problem is with MX 2004.

Has anyone had any problems with this or know how I might be able to fix it? I have downloaded the updater (do I have to run the updater or dose it update automatically?) but have not tried a fresh reinstall.

Any ideas?