Hi Ivan,
It looks like skin extension plugins are not loaded in your XE. You can try:
{{velocity}}
$xwiki.ssx
{{/velocity}}
And see if it outputs the plugin API object.
Also, can you check whether your xwiki.cfg file has the plugins declared
like:
#-# List of active plugins.
xwiki.plugins=\
com.xpn.xwiki.monitor.api.MonitorPlugin,\
com.xpn.xwiki.plugin.skinx.JsSkinExtensionPlugin,\
com.xpn.xwiki.plugin.skinx.JsSkinFileExtensionPlugin,\
com.xpn.xwiki.plugin.skinx.CssSkinExtensionPlugin,\
com.xpn.xwiki.plugin.skinx.CssSkinFileExtensionPlugin,\
.....
If you are sure that your xwiki.cfg is correct, you should see some
exception traces when you start XE. These exceptions will complain that some
plugins are missing or was not loaded due to errors.
If you can try the above and post the tomcat logs for missing / errornous
plugins, may be we can help.
Thanks.
- Asiri