Firefox 4 is causing conflicts with the Eircom Webmail Zimbra email system.
Since updating to Firefox 4 many people are unable to open folders in Eircom Webmail. Eircom Support say that Firefox 4 is causing conflicts with their Zimbra email system.
Wšykne wótegrona (2)
Try using this extension:
https://addons.mozilla.org/en-US/firefox/addon/remote-xul-manager/
This extension does not solve problem.