upload one your fla's to a files server and post a link here.
i've seen this a few times but never on multiple files or consistantly.
double-click on a symbol's icon in the library to go into symbol-edit mode, then click back out to the scene 1 timeline by clicking on the Scene 1 button up top.
that usually works, or try resetting your workspace. window > workspace > reset 'some workspace'
The contents of your user configuration folder and preferences might be corrupted.
Please try this:
1. Navigate to C:\Users\<user name>\AppData\Local\Adobe\.
2. Rename Flash CS4 folder to some other name.
3. Relaunch Flash.
Note that relaunching Flash will create a new Flash CS4 folder. Now see if the stage is still blank when you open your files.
If this solves your problem, switch back to the old Flash CS4 folder (make sure to rename it back to Flash CS4) and see if the problem comes back. If the problem came back, please zip the problematic Flash CS4 folder. Rename the extension .zip to .zzz and email it to me at FlashAuthBetaBugs@adobe.com.
i have the same Problem. My Stage is always emtpy. When i start a new Projekt i can draw on the stage, but when is stop painting the line dissapears. when i drag elements on the stage, nothings happens.
It seems, that the objects are on the stage, but they arent visible.
When i export those swf files, everything is okay.
Thank you for help.