Since then, IDEA creashes with a core dump whenever the server starts (even though it always starts successfully)

I've launched IDEA using the bat file to be able to see if anything is written to System err, and here is the result

29 nov. 2007 14:40:33 com.ibm.websphere.management.AdminClientFactory
ATTENTION: ADMC0046W
29 nov. 2007 14:40:34 com.ibm.ws.management.connector.interop.JMXClassLoader
ATTENTION: Could not find tmx4jTransform.jar in null/etc/tmx4jTransform.jar - Interoperability to older versions of WebSphere is disabled
29 nov. 2007 14:40:35 com.ibm.ws.ssl.config.SSLConfig
ATTENTION: ssl.default.password.in.use.CWPKI0041W
29 nov. 2007 14:40:35 com.ibm.ws.ssl.config.SSLConfigManager
INFO: ssl.disable.url.hostname.verification.CWPKI0027I
#

1. An unexpected error has been detected by Java Runtime Environment:
   #
2. Internal Error (43113F2C2932215353454D424C45523F491418160E4350500470), pid=2788, tid=3676
   #
3. Java VM: Java HotSpot(TM) Client VM (1.6.0_02-b05 mixed mode)
4. An error report file with more information is saved as hs_err_pid2788.log
   #
5. If you would like to submit a bug report, please visit:
6. http://java.sun.com/webapps/bugreport/crash.jsp
   #

I'm also joining one of the crash dump

Launching the same server when security is not active works like a charm