Comment 22 for bug 966244

not sure if this addresses your problem or not, but I should mention that the default unit of measure in Inkscape is the pixel at resolution 90 dpi. In a program like Illustrator it is quite likely that they are using points at a resolution of 72 dpi. The ratio of the two is 1.25.
    Other than that, if that is not the issue, could you submit an svg file which illustrates the problem?