strange behavior of ex constructor from string

I'm currently testing the latest version of the Z-factorization code and found some weierd results that I believe show there is a bug in the ex constructor from a string. You can reproduce this bug the following way: compile the latest ftp://fourier.ujf-grenoble.fr/pub/hp48/giac.tgz (make install then make factor) Try ./factor zimmer7 answer is 0 Looking in my code, it seems that the call args.push_back(ex(string(ss2),lst(sym))); line 480 of polygauss.cc pushes a 0 instead of the correct expression (i.e. what's in the zimmer7 file) (you can check this by putting a breakpoint in factor.cc, l.27, p it->dbgprint() prints 0) The same call works when applied to zimmer1, zimmer2, zimmer3. Any ideas? Bye, Bernard