It is not that easy to get to the log, becaouse the site is craching all the time :)
I found this:
An error has occurred.
DotNetNuke.Services.Exceptions.PageLoadException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.Services.Localization.Localization.GetResource(String ResourceFileRoot, PortalSettings objPortalSettings, String strLanguage) at DotNetNuke.Services.Localization.Localization.GetString(String name, String ResourceFileRoot, PortalSettings objPortalSettings, String strLanguage) at DotNetNuke.Services.Localization.Localization.GetString(String name, String ResourceFileRoot) at DotNetNuke.Services.Localization.Localization.LocalizeTabStripDetails(ArrayList arrTabStripDetails) at DotNetNuke.Services.Localization.Localization.LocalizePortalSettings() at DotNetNuke.Framework.PageBase.OnInit(EventArgs e) at System.Web.UI.Control.InitRecursive(Control namingContainer) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace ---
It is something with the localization...