Question : why do i get "No mapping for the Unicode character exists in the target multi-byte code page"

I have a website running on iis7 and windows server 2008 when i try to access it with mozzila firefox from some computers i get "System.ArgumentOutOfRangeException: No mapping for the Unicode character exists in the target multi-byte code page. (Exception from HRESULT: 0x80070459)"

Answer : why do i get "No mapping for the Unicode character exists in the target multi-byte code page"

Is the correct charset defined in the "content-type" header?
Since you probably are using Hebrew characters, this charset will have to be ISO-8859-8 or utf-8, I guess.

For HTML:


For XHTML: