i got error when click any link in the K2 manager site inside my web application (Action Right , Error Log,Instant Managment - All , Instant Managment - Active ,,, etc)

the wired thing is the page open normaly when i open the url from WFE or Application server , and i got this error when i open the url from outside those servers.

where i can find the K2 resources file ?!

any one can help me here

the error in the sharepoint log file is

System.Web.HttpException: The resource object with key 'ErrorLogsPage_Title' was not found.    at System.Web.Compilation.ResourceExpressionBuilder.ParseBLOCKED EXPRESSION     at System.Web.UI.ControlBuilder.AddBoundProperty(String filter, String name, String expressionPrefix, String expression, ExpressionBuilder expressionBuilder, Object parsedExpressionData, Boolean generated, Strin... d0606421-985c-43d2-bb52-82c2f8b400da