If libtag.a is a static library, you need to add -DTAGLIB_STATIC to the compiler flags. (I do this by providing a DEFINE=-DTAGLIB_STATIC argument to the 'perl Makefile.PL' command.)
However, I don't know if that relates to the error message you received and, since a downgrade to version 1.11 is likely of little importance, it probably doesn't matter ;-)