[CentOS] tomcat error on x86_64 with 2.6.18-8.1.8.el5xen & jre 1.6.*

I get the same error as this person:
http://www.centos.org/modules/newbb/viewtopic.php?topic_id=9349

Like the poster, I get the error with tomcat 6.0.13 on 
x86_64, kernel 2.6.18-8.1.8.el5xen and both jre 1.6.0_01 and 
1.6.0_02

When I revert to jre 5u12 on the same kernel, I don't get 
the problem.

If I stay with jre 6, but use kernel 2.6.18-8.el5, I also 
don't get the error.


So it's not clear to me whether this is a java problem or a 
kernel problem. Any hints?

For now, I can use jre 5u12, but I could file a bug if I 
could figure out which one is actually causing the error.

johnn