Can you please provide the rest of the output? Everything that was printed in the syslog around that line.
You mean this?
/boot/config# install simpleFeatures.itunes.server-1.0.11-noarch-1.plg
install: missing destination file operand after `simpleFeatures.itunes.server-1.0.11-noarch-1.plg'
Try `install --help' for more information.
Can you try 'installplg' instead of 'install'?
Also, run the command as root.
Trying installplg I get this:
"installplg simpleFeatures.itunes.server-1.0.11-noarch-1.plg
installing plugin: simpleFeatures.itunes.serversimpleFeatures.itunes.server-1.0.11-noarch-1
installing plugin: simpleFeatures.itunes.server-1.0.11-noarch-1
file /tmp/plugin-prepare: successfully wrote INLINE file contents
/bin/bash /tmp/plugin-prepare ... success
file /boot/plugins/simpleFeatures/simpleFeatures.itunes.server-1.0.11-i486-1.txz: already exists
upgradepkg --install-new /boot/plugins/simpleFeatures/simpleFeatures.itunes.server-1.0.11-i486-1.txz ...
+==============================================================================
| Skipping package simpleFeatures.itunes.server-1.0.11-i486-1 (already installed)
+==============================================================================
success
file /boot/plugins/simpleFeatures/simpleFeatures.itunes.server.png: already exists
file /usr/local/emhttp/plugins/simpleFeatures.itunesServer/images/itunes.png: already exists
file /boot/packages/sqlite-3.7.14.1-i486-1.txz: downloading from http://slackware.cs.utah.edu/pub/slackware/slackware-current/slackware/ap/sqlite-3.7.14.1-i486-1.txz ... http://slackware.cs.utah.edu/pub/slackware/slackware-current/slackware/ap/sqlite-3.7.14.1-i486-1.txz:
2013-07-20 23:11:48 ERROR 404: Not Found.
bad download, deleting"