[xwiki-users] Problem installing xWiki

Hi all, I'm I'm trying to install /xwiki-enterprise-2.7.1 on Tomcat 6. And I have the following Java error: [...] SEVERE: The web application [/xwiki-enterprise-2.7.1] created a ThreadLocal with key of type [org.apache.log4j.helpers.ThreadLocalMap] (value [org.apache.log4j.helpers.ThreadLocalMap@15ef45a]) and a value of type [java.util.Hashtable] (value [{url=http://localhost:8888/xwiki-enterprise-2.7.1/bin/view/Main/}]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. log4j:ERROR Error occured while converting date. java.lang.NullPointerException at java.lang.System.arraycopy(Native Method) at java.lang.AbstractStringBuilder.getChars(AbstractStringBuilder.java:345) at java.lang.StringBuffer.getChars(StringBuffer.java:218) at org.apache.log4j.helpers.ISO8601DateFormat.format(ISO8601DateFormat.java:130) at java.text.DateFormat.format(DateFormat.java:333) [...] I didn't have the 'common' dir hanging on $TOMCAT_HOME dir, so I copied from another tomcat instance which is working OK. I created log4j.properties according xwiki web, but I have the same error. Database connection is Oracle, and I don't know what to do. Any ideas? Regards,