At the end I solved problem. For the other users I will write my explanations. I am using Glassfish v.3. Initialy I have error when I trying lo upload ANY xar-file on versions 2.3.2 and 2.4 of XE (also for fresh install I cannot upload full XE xar-file): Wrapped Exception: org.apache.commons.codec.binary.Base64.<init>(I[B)V com.xpn.xwiki.XWikiException: Error number 0 in 11: Uncaught exception Wrapped Exception: org.apache.commons.codec.binary.Base64.<init>(I[B)V ... Versions XE before 2.3 (2.2.6, 2.1) didn't generate any errors and upload working fine on it. I started to make some investigation and found that - Glassfish has a problem when different versions of the same library exist both in a webapp and it its system library. This means that needs to replace commons codec library in a glassfish modules folder with the same library from the XE lib folder. Details - http://jira.xwiki.org/jira/browse/XE-690 -- View this message in context: http://xwiki.475771.n2.nabble.com/Re-Upgrade-from-2-2-to-2-4-RC-1-base64-ini... Sent from the XWiki- Users mailing list archive at Nabble.com.