Why would you want a core dump? Do you think it's a problem of your OS? Pls post what you did with what OS, what Java, what client - don't forget to mention the Bit version...
Problem solving
1. Have OS and all drivers updated
2. Have latest Java installed
viewtopic.php?f=2&t=28086#p3594123. test your Java:
http://java.com/en/download/testjava.jsp4. make exeptions for (open) TCP port 1871 and UDP port 1870 in your firewall
5. Press "Play"
6.
Open autohaven file
with Java (TM) Web Start Launcher7. Let it download needed files
8. login and play
alternative (5. - 8.):
viewtopic.php?f=27&t=14575download Ender client (same Bit version as your installed Java!) and update.zip
unpack update.zip into Ender folder
edit run.bat inside Ender folder to make it point to your Java path
edit a new line in with only the word "pause" (that way CMD window stays open to show error messages)
Start -> run -> Path to Ender folder run.bat -> ok
login and play
Be aware that you might get the message: "Can't connect to server" sometimes - just try it again...
Report back pls