Hi .. just to throw in my 2 cents of wisdom ..
Refills can be used on both platforms @ 3rdfloor

, and for the version you are installing ... , did you bought it , or download it ? ( The reason why i ask you , is because i know that the original is hybrid ( same cd for windows and osx ...) , and i dont know if you downloaded your copy , cos then there could be something wrong with the hybrid structure ...
IF All above aint the thing ... then the following came to my mind :
Harddisk settings on the OSX ? , privacy settings ? ( Dont even know IF OSX got something like it , but i thought .. ill give it a shot

)
Greetzzzzzzzzzz and good luck ...!