Troubleshooting: Error encountered when running multiple WebSphere Commerce Update Installer processes at one time

When using the WebSphere Commerce Update Installer to install a fix pack or APAR, you receive a INSTCONFFAILED message.

Problem

When completing a silent installation, you encounter an error in the WC_installdir/logs/update/unknown.install/updatelog.txt file similar to:
(Jan 29, 2011 2:57:04 AM), Install, com.ibm.ws.install.ni.ismp.actions.
PopulateTitleBarAction, msg1, WebSphere Commerce Update Installer V7.0.0.2
(Jan 29, 2011 2:57:04 AM), Install, com.ibm.ws.install.ni.ismp.actions.
ISMPFileDeleteAction, msg1, Deleting file: Source: /tmp/.aix_ISMP_lock____
(Jan 29, 2011 2:57:05 AM), Install, com.ibm.ws.install.ni.ismp.actions.
SettleNIFRegistryAction, msg1, Current install/uninstall process failed.
(Jan 29, 2011 2:57:05 AM), Install, com.ibm.ws.install.ni.ismp.actions.
SetExitCodeAction, msg1, CWUPI0000I: EXITCODE=1
(Jan 29, 2011 2:57:06 AM), Install, com.ibm.ws.install.ni.ismp.actions.
ISMPLogFileAction, msg1, For more information about installing components, 
see the following trace file:
/usr/WebSphere/CommerceServer60/logs/update/unknown.install/updatetrace.log.gz 
(Jan 29, 2011 2:57:06 AM), Install, com.ibm.ws.install.ni.ismp.actions.
ISMPLogFileAction, msg1, For more information about running configuration commands, 
see the following trace file:
/usr/WebSphere/CommerceServer60/logs/update/unknown.install/updateconfig.log.gz
(Jan 29, 2011 2:57:06 AM), Install, com.ibm.ws.install.ni.ismp.actions.
ISMPLogSuccessMessageAction, msg1, INSTCONFFAILED

Solution

If you encounter this problem, ensure that you do not have multiple Update Installer processes running. If there are no additional processes running, launch the Graphical User Interface install and progress through the install panels for more information.