I have a couple of customers that cannot get flash to display in their browser with SWFObject. Flash works fine with the standard <OBJECT> code. Java script is enabled for both of them. One has IE6 and the other has IE7.
I have many customers and have used swfobject for over a year, without problems. But these two problems showed up in the past week and I am wondering if this is a new problem and I am going to see a whole lot more of this.
I think it would be a machine specific issue like bad flash install etc. Also, are you sure js is enabled for them? (do they see the alert boxes pop up etc?)