Hi Johnny,
I am having the same pink tile problem.. (using IIS5 hosting the map and open it on IE8 on Windows xp professional 2002 + SP3; firefox doesn't show the pink tiles but missing pieces. )
i right click on the pink tiles and it shows me the images properly in another tab.
i checked the error on IE. it says something like following:

When i drag the map to move a round away from the pink tiles and move back there.. the the images show up to replace the pink tiles.
I also used httpWatch to check.. the pink tile should be matching with the 403 http error
Do you know the possible reason for my case and how i can solve the pink tile problems.?
Thanks a lot!
Lishan