pgrpm - pgrpm: - improve errcode and error messages

Log Message:
-----------
- improve errcode and error messages

Modified Files:
--------------
pgrpm:
ChangeLog (r1.11 -> r1.12)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgrpm/pgrpm/ChangeLog.diff?r1=1.11&r2=1.12)
pgheader.c (r1.29 -> r1.30)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgrpm/pgrpm/pgheader.c.diff?r1=1.29&r2=1.30)