What do you mean by "safe mode?" Is your computer shutting down when you open a PDF and then booting back up in safe mode?
Is your antivirus software or firewall software giving some kind of warning?
The reason I'm asking is, there is no such thing as running a program in safe mode in Vista while maintaining a session. You'd have to restart your computer to run Vista in safe mode.
If it's some sort of dialog box informing you of something going on, and it's not the Blue Screen Of Death, can you screenshot the message for us, please?
1) First, open up MS Paint.
2) Open up Adobe or a PDF.
3) When the error message or whatever happens, happens, hit the "Print Screen" key on your keyboard.
4) Go to MS Paint.
5) Paste. <Control>+<V> or from the Edit menu, either way works. You'll see your whole desktop as an image in Paint.
6) Go to the Image menu, select "Crop," and use the cursor to box in whatever it is that's telling you about safe mode.
7) Go back to the Image menu and select Crop again to crop the image to just that dialog box or whatever it is.
8) Save it to a Photobucket account and copy the image's URL location.
Insert the image into your reply to this thread.