Workflow is failing with below error,can you please help me
System.ArgumentException: String cannot be of zero length. Parameter name: oldValue at System.String.ReplaceInternal(String oldValue, String newValue) at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext() at Abbott.Workflow.ProductWorkflow.MasterWorkflow.PublishToStaging.Execute() at Tridion.ContentManager.CoreService.Workflow.ExternalActivity.ExecuteInternal(String activityInstanceId, String processInstanceXml, Action action) at Tridion.ContentManager.CoreService.Workflow.ExternalActivity.Tridion.ContentManager.Workflow.IExternalActivity.Execute(String activityInstanceId, String processInstanceXml) at Tridion.ContentManager.Workflow.ExternalActivityExecutor.ExecuteScript(String script, String currentActivityInstanceId, String processInstanceXml) at Tridion.ContentManager.Workflow.WorkflowAgentEngine.<>c__DisplayClass7.b__1() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at Tridion.ContentManager.Workflow.WorkflowAgentEngine.ProcessActivity(TcmUri activityInstanceId, Boolean isExpirationExecution)