after more googling, found solution to the MYSQL connection in mysql.com forum:
[
forums.mysql.com]
in short, this is a windows 7 dependency issue. in windows/sys32/driver/etc/host file, there's a line
::1 localhost
simply comment it out and problem solved. so something in php 5.3.1 caused apache to have issue with this localhost setting that was ok in php 5.2.6.
well, hopefully all these will be helpful to others who encounter the same issues. am i the only one adding php 5.3.1 in wamp 2.0?