Error after upgrading to 2.0.0.4

Hello,

I replaced my 1.5 files with the new 2.0.0.4 version. It kept all the data, but I have an error message down the bottom of the interface:

No chrome package registered for chrome://messenger-offline/locale/offline.dtd .

Error: undefined entity
Source File: chrome://messenger-offline/content/msgOfflineOverlay.xul
Line: 26, Column: 5
Source Code:
<menu id="offlineMenuItem" insertafter="trashMenuSeparator" label="&offlineMenu.label;" accesskey="&offlineMenu.accesskey;">----^


I don't have scrollbars either for the list of messages in my inbox.

Thanks,
Xan.