Sometimes different browsers interpret uppercase and lowercase letters as being different chars ie K != k. Make sure that in your html/xml you are explicitly referencing the correct resources being case sensitive.
Also, make sure that you have the correct slashes (/ and \) setup correctly. Generally the assumption should be always use a /
Not sure if this is the problem from the limited description that you gave, but it definately could be one of the fixes considering that it works in one browser and not the next.