>You should only open the .ai file

Hi Michael,

sorry I wasn't clear enough. I have both files in a folder. When I double click the .ai file nothing happens. It just doesnt open.
When I delete the .png file and then double click the .ai file I get a warning that a linked file is missing. If I push "Ignore" in that window the .ai file opens and I can see the lines.
I tried this on a second computer with the same setup and same result.

I also can't place the .png file into Illustrator. There seems to be a problem with large png files and/or transparency according to http://forums.adobe.com/thread/478570 or http://forums.adobe.com/thread/668668

This works:
I opened the .png in Photoshop and saved it as .psd file. Then I deleted the original png file. When I double clicked the Illustrator file I chose replace in the missing file warning window and then chose the .psd file. Now it opened fine.

I'm very happy with the result and the extra conversion doesn't bother me.