I've had this problem in 2005 -- it's a pain. Can you tell me how you're defining where ie.css is placed? If the site.master defines it as "style/ie.css" then it's possible the Header.ascx also looks there, but this relative path becoms "/ctrl/style/ie.css" and VS complains. I don't really have a fix though, sorry, just if that's the problem then there might be ways to address is....
Noah Blumenthal
Computer Innovations
email/gtalk: noah [at] computerinnovationsny.com
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