I found the solution and mention it in here in case somebody else faces similar situation. The problem arose due to the fact that I uses:
axis([0 inf 0 10])
normally, Matlab interprets 'inf' in axis command as a hint to specify the upper bound of the axis itself, which is does and the plot is OK. But for some reason, plot2svg has an issue with that. Changing it to something like:
axis([0 5 0 10])
will fix the problem.
It is very helpful, specially for somebody like me who wants to export figures to LaTex (through inkscape). I have successfully used plot2svg for a figure and it worked perfectly, however, for another figure, I got the following message:
Matlab/Octave to SVG converter version 10-Nov-2010, Juerg Schwizer (firstname.lastname@example.org).
Warning: The fourth output, VERSN, of FILEPARTS will be removed in a future release.
> In fileparts at 35
In plot2svg at 182
Warning: NaN found in Y, interpolation at undefined values
will result in undefined values.
> In interp1 at 179
In plot2svg>gridLines at 709
In plot2svg>axes2svg at 975
In plot2svg at 221
and the warning goes on and on for every 'gridline' following the first. And the output is almost empty. It is a 3x2 subplot with two titles, 6 ylabels and 2 xlabels.