Since I added
to my CSS, my Cookies which i set in the Backend are not working anymore.
If i remove behavior: url(PIE.htc); from my CSS my cookies are working well.
BTW: The PIE-Fallbacks are working very well
This solved my Problem:
1 use a CC for PIE
2 the must have a "/" at the beginning
Then i have no issues with my cookies and PIE is still working