Thank you for the help. I think it was just a caching problem. I tried themightyatoms tip and opened the dae file inside the browser (it displays as a normal text document, no XML structure) and afterwards the model was loading up. Very strange. If you want to test it: http://demo.visionsbox.de/flar/ (it's an AR Demo, so print out the PDF marker (link below the camera box); use arrow keys to move the object; dae is 1mb so please wait a bit; traces are still in so you can use FlashTracer to see the bytesLoaded info).
I used the "./test.dae" to solve the folder bug in dae. There was a posting somewhere that you need to use "./" if its in the same folder. Would be nice if someone would fix that because that took me a while to figure it out.
