The jre with the current version of OpenFire is 1.7.0.51 - and it looks like you are using a 1.6.* version. 3.9.0 might possibly require a 1.7 JRE to work.
You should grab the .rpm of 3.9.0, and use rpm -Uvf to update your currently installed OpenFire, and that would probably fix your segfaults…
I glanced over the logs and didn’t see anything glaring. Are you able to observe the memory usage before the crash? I have you tried doubling the allocation and see if it crashes?
You won’t be able to use 64bit JVM as it appears your machine is 32bit.