Error number 3 in 0: Could not initialize main XWiki context WEN use Oracle 10.2

I configure and use MySql and all works; when I switch to Oracle 10.2 (after creta tablespace, user and grant for xwiki/xwiki and configure hibernate.cfg.xml) and start application using http://localhost:8080/xwiki, I receive thi error:

HTTP Status 500 -

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type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Error number 3 in 0: Could not initialize main XWiki context
Wrapped Exception: Error number 3202 in 3: Exception while reading document XWiki.XWikiPreferences
Wrapped Exception: Could not find a getter for comment in class com.xpn.xwiki.objects.classes.BaseClass
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:535)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:433)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:118)

root cause

com.xpn.xwiki.XWikiException: Error number 3 in 0: Could not initialize main XWiki context
Wrapped Exception: Error number 3202 in 3: Exception while reading document XWiki.XWikiPreferences
Wrapped Exception: Could not find a getter for comment in class com.xpn.xwiki.objects.classes.BaseClass
com.xpn.xwiki.XWiki.getMainXWiki(XWiki.java:292)
com.xpn.xwiki.XWiki.getXWiki(XWiki.java:384)
com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:96)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:118)

note The full stack trace of the root cause is available in the Apache Tomcat/5.5.23 logs.

(no table was created into DB for user xwiki)

tnx.