I want to mask a svg file to image , get error

[jonny77]

svg file content:

<?xml version="1.0" standalone="no"?>
        <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">

<svg width="100%" height="100%" version="1.1" xmlns="http://www.w3.org/2000/svg">
    <defs>
        <linearGradient id="orange_red" x1="100%" y1="0%" x2="100%" y2="100%">
            <stop offset="0%" style="stop-color:rgb(255,182,130); stop-opacity:1"/>
            <stop offset="100%" style="stop-color:rgb(255,135,88); stop-opacity:1"/>
        </linearGradient>
    </defs>
    <rect width="668" height="376" style="fill:url(#orange_red)"/>
</svg>