reproduced with Inkscape 0.47 and 0.48+devel r9640 on OS X 10.5.8
The gradients in the original SVG [1] are not stored in the <defs> section but directly in the root <svg> element. They are dropped when importing the SVG file with 'File > Import' and all paths which only have a gradient fill but no stroke are not rendered visibly (but visible in outline mode).
reproduced with Inkscape 0.47 and 0.48+devel r9640 on OS X 10.5.8
The gradients in the original SVG [1] are not stored in the <defs> section but directly in the root <svg> element. They are dropped when importing the SVG file with 'File > Import' and all paths which only have a gradient fill but no stroke are not rendered visibly (but visible in outline mode).
[1] <!-- Generator: Adobe Illustrator 13.0.0, SVG Export Plug-In . SVG Version: 6.00 Build 14948) -->