[xwiki-devs] Error number 3 in 0

Hi, i have this error since yesterday and all i did is trying to add a excel plugin so i followed the tutorial , i added the jxl jar in lib directory and i putted the line in xwiki.cfg but after having this error i rolled back all my changes i deleted the jar and restored the xwiki.cfg to the same old state but still have the error: HTTP ERROR: 500 Error number 3 in 0: Could not initialize main XWiki context Wrapped Exception: Error number 3001 in 3: Cannot load class com.xpn.xwiki.store.migration.hibernate.XWikiHibernateMigrationManager from param xwiki.store.migration.manager.class Wrapped Exception: Error number 0 in 3: Exception while hibernate execute Wrapped Exception: invalid configuration RequestURI=/xwiki/bin/view/Main/ Powered by Jetty:// what should i do, my work is lost? help on this one please thank you very much -- View this message in context: http://n2.nabble.com/Error-number-3-in-0-tp2642272p2642272.html Sent from the XWiki- Dev mailing list archive at Nabble.com.