Same problem with Debian4-etch-amd64 and IO::AIO. On installation perl Makefile.pl looks good, make builds the file, but make test won't pass: Can't load '/usr/src/IO-AIO-3.1/blib/arch/auto/IO/AIO/AIO.so' for module IO::AIO: /usr/src/IO-AIO-3.1/blib/arch/auto/IO/AIO/AIO.so: undefined symbol: SvREFCNT_inc_NN at /usr/lib/perl/5.8/DynaLoader.pm line 225. at /usr/lib/perl/5.8/DynaLoader.pm line 218