VM settings can very. It all depends on your host running your server.
My personal settings i put 32-40 gigs of ram. 150-200 gigs of hdd (because i can lol), you only need about 40 gigs.
Network settings I do bridged adaptor. This will share the same internet access as your host. If you said you updated to 1.5.5 you need to go back and check your ports. hostnames etc. there are some videos on how to set up your server on YouTube. Ill leave a link or 2 that shows u how.
how to make a pwi server - YouTube
HOW TO CREATE A 1.5.3 PERFECT WORLD SERVER (TUTORIAL) - YouTube
You can make sure that your pwadmin is working by going to your terminal on your vm and type the following commands.
server pwAdmin start
server pwAdmin status.
pwAdmin does comunicate to your phpmyadmin for accounts etc.
here is the format to access the pwadmin page
http://0.0.0.0<---(your vm ip address)/pwAdmin
if thats not working then you have done something wrong and will have to check your config files.
Hope this helps.