Are you sure, the latest 2007c timezone info for /Canada/Pacific is correct(this is from a RHEL/CentOS/SL updated rpm package);
$ zdump -v /usr/share/zoneinfo/Canada/Pacific |grep 2007
/usr/share/zoneinfo/Canada/Pacific Sun Mar 11 09:59:59 2007 UTC = Sun Mar 11 01:59:59 2007 PST isdst=0 gmtoff=-28800
/usr/share/zoneinfo/Canada/Pacific Sun Mar 11 10:00:00 2007 UTC = Sun Mar 11 03:00:00 2007 PDT isdst=1 gmtoff=-25200
/usr/share/zoneinfo/Canada/Pacific Sun Nov 4 08:59:59 2007 UTC = Sun Nov 4 01:59:59 2007 PDT isdst=1 gmtoff=-25200
/usr/share/zoneinfo/Canada/Pacific Sun Nov 4 09:00:00 2007 UTC = Sun Nov 4 01:00:00 2007 PST isdst=0 gmtoff=-28800
Perhaps you want to review and verify you have the latest:
http://www.linuxsecurity.com/content/view/127260/106/