Thanks. Be sure I though of that before.

My own modules start to setup @INC with use dir at their very beginning: that's not the problem, it works pretty well. But each script must do that to load the initial common module: this is not clean.

AFAIK, Inkscape calls an executable called perl.exe without any parameter. It IS possible to modify this under Unices via a preference.xml file, but this file does not exist in the windows version and I do not have access to the process environment to setup a variable at startup.

But this is not the real part of the problem: it requires an external Perl installation and Straberry Perl is a fat thing that casual users of extensions definitely don't need (they don't need a Unix environment). This is why the Inkscape Team included Python in their distribution and why I'd like to do the same with Perl. And Active Perl is not, strictly speaking, free software and this I don't like.

And last but not least, I've always hated this Python vs Perl discrimination ;)