Hello. I've installed IntelliJ IDEA 9.0 and I was testing support for Adobe Flex. Everything was working fine except that I was not able to connect to Flash debugger. Later I found that IDEA was not able to connect to to network at all. Linux 2.6.32. The problem was, that IPv6 was enabled. For some reason IDEA was using this network layer instead of IPv4.
Solution: Just disable IPv6. Here I wrote few notes (for English version hit translate button): http://georgik.sinusgear.com/2010/02/27/intellij-idea-9-0-na-linuxe-nefunguje-siet-pozor-na-ipv6/
You can disable IPv6 by using kernel option: ipv6.disable=1 - http://www.cyberciti.biz/tips/linux-how-to-disable-the-ipv6-protocol.html