I get:

15:10:39,867 |-INFO in ch.qos.logback.core.joran.action.StatusListenerAction - Added status listener of type [com.evry.fs.tac.lbe.LogbackListener]
15:10:39,898 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - About to instantiate appender of type [ch.qos.logback.core.rolling.RollingFileAppender]
15:10:39,903 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - Naming appender as [LOGFILE]
JVMDUMP006I Processing dump event "abort", detail "" - please wai

when running on a:
bash-4.2$ /usr/java7/bin/java -version
java version "1.7.0"
Java(TM) SE Runtime Environment (build pap3270-20110827_01)
IBM J9 VM (build 2.6, JRE 1.7.0 AIX ppc-32 20110810_88604 (JIT enabled, AOT enabled)
J9VM - R26_Java726_GA_20110810_1208_B88592
JIT - r11_20110810_20466
GC - R26_Java726_GA_20110810_1208_B88592
J9CL - 20110810_88604)
JCL - 20110809_01 based on Oracle 7b147
bash-4.2$

the exact same configuration /commandline runs fine with:
bash-4.2$ /usr/java6/bin/java -version
java version "1.6.0"
Java(TM) SE Runtime Environment (build pap3260sr9fp2-20110627_03(SR9 FP2))
IBM J9 VM (build 2.4, JRE 1.6.0 IBM J9 2.4 AIX ppc-32 jvmap3260sr9-20110624_85526 (JIT enabled, AOT enabled)
J9VM - 20110624_085526
JIT - r9_20101028_17488ifx17
GC - 20101027_AA)
JCL - 20110530_01
bash-4.2$

One thing I have noticed is that if I point logback on a non-existing configurationfile with:
-Dlogback.configurationFile="$BASEDIR"/etc/cashpool/logback.xml_nonexisting

it will run ok (but obviously with invalid/no configuration).

Same problem will occur if logback is configured by looking in default location rather than being pointed explicitly on the file.