Problem with Flash 8 and HTML frames

Hi to everyone, I’m developing a website with frames. I’ve got a fixed left frame with a flash menu, and I want to load html content in the mainFrame. I’m using getURL (“welcome.html”,“mainFrame”); but it doesn’t work. It opens the welcome.html into a new window, and I know that this happens when the frame doesnt exists… but the frame exist. Please, can someone help me? I’m working on Mac OSX

Some more info: I’m using nested frames to center the site, so the frames I’m talking about are in 3rd level. Thx.