OptString parameters can be NULL. Not all of the bindings really handle this case - probably they segfault if presented with a NULL parameter. We also need to add an automated regression test which tests this case.
Related to this is bug 501893 (String parameters should be checked for != NULL)
Moving upstream, just a safety check
This is fixed upstream by http://git.et.redhat.com/?p=libguestfs.git;a=commitdiff;h=babc0846cc911b01a58a7385d30ad25889b7175a
libguestfs-1.0.36-1.fc11.2 has been submitted as an update for Fedora 11. http://admin.fedoraproject.org/updates/libguestfs-1.0.36-1.fc11.2
libguestfs-1.0.38-1.fc11 has been submitted as an update for Fedora 11. http://admin.fedoraproject.org/updates/libguestfs-1.0.38-1.fc11
libguestfs-1.0.41-1.fc11 has been submitted as an update for Fedora 11. http://admin.fedoraproject.org/updates/libguestfs-1.0.41-1.fc11
libguestfs-1.0.42-1.fc11 has been submitted as an update for Fedora 11. http://admin.fedoraproject.org/updates/libguestfs-1.0.42-1.fc11
libguestfs-1.0.51-1.fc11 has been submitted as an update for Fedora 11. http://admin.fedoraproject.org/updates/libguestfs-1.0.51-1.fc11
libguestfs-1.0.54-2.fc11 has been submitted as an update for Fedora 11. http://admin.fedoraproject.org/updates/libguestfs-1.0.54-2.fc11
libguestfs-1.0.55-1.fc11 has been submitted as an update for Fedora 11. http://admin.fedoraproject.org/updates/libguestfs-1.0.55-1.fc11
libguestfs-1.0.58-2.fc11 has been submitted as an update for Fedora 11. http://admin.fedoraproject.org/updates/libguestfs-1.0.58-2.fc11
libguestfs-1.0.54-2.fc11 has been pushed to the Fedora 11 stable repository. If problems still persist, please make note of it in this bug report.
libguestfs-1.0.58-2.fc11 has been pushed to the Fedora 11 stable repository. If problems still persist, please make note of it in this bug report.
Long fixed upstream.