Quoth Joshua A. Andler on or about 2004-11-10:
I just busted open Illustrator 10 and it opened an Inkscape SVG file ok. The results weren't perfect though. If you have any raster image within the SVG that was resized in inkscape, it defaults back to the original size in Illustrator. Also, it totally ditches any transparencies (whether on the object level or within a color/gradient). Luckily it still keeps the gradients as they are though.
So you may just want to try and open directly in Illustrator if you or the person you're sending it to have a relatively recent version.
Were you testing an Inkscape SVG or `plain SVG'?
If you fix and save the SVG in Illustrator, how does the SVG differ from the original `plain' SVG? It might require trivial changes to produce the Illustrator-readable file.
-trent