Settings look okay. FYI, when a previous user had this previous symptom, I created a simple version (I think the issue was local playback); I could not get the grey screen, unless I moved the "sources" folder or renamed other assets.
Do you see anything on the grey screen (buttons/highlights)?
You can get problems if your flash security settings don't handle local playback. E.g you may be able to play from web and not locally. You can also get issues for web playback if your host settings are incorrect.
Are you playing locally (on your computer) or have you uploaded and are playing from the web?
In the folder where the index.html file is located, you should see 4 files (ignore the .txt file below). In the "sources" folder, you hvae one or more .flv/.f4v files, and image files - jpg is the menu backgroud and png's are highlights.
