Value cannot be null. Parameter name: String - Asp.net Umbraco site

Please check once the error stack and advise why the error happens and what is the solution for that. I am getting lots of error like that. This is Asp.net Umbraco site.

Full Stack Trace :

System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. 
--> System.ArgumentNullException: Value cannot be null. Parameter name: String
 at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
 at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
 at ASP.usercontrols_adviserprofileright_ascx.__Render__control1(HtmlTextWriter __w, Control parameterContainer)
 at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
 at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
 at System.Web.UI.Control.Render(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
 at umbraco.presentation.templateControls.Macro.Render(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
 at ASP.masterpages_adviser_master.__Render__control6(HtmlTextWriter __w, Control parameterContainer)
 at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
 at System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer)
 at System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer)
 at System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output)
 at umbraco.presentation.urlRewriter.FormRewriterControlAdapter.Render(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer)
 at ASP.masterpages_adviser_master.__Render__control2(HtmlTextWriter __w, Control parameterContainer)
 at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
 at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
 at System.Web.UI.Control.Render(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
 at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
 at umbraco.presentation.masterpages._default.Render(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
 at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
 at System.Web.UI.Control.Render(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
 at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
 at umbraco.UmbracoDefault.Render(HtmlTextWriter writer)
 at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
 at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
 at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
 at System.Web.UI.Page.HandleError(Exception e)
 at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
 at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
 at System.Web.UI.Page.ProcessRequest()
 at System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context)
 at System.Web.UI.Page.ProcessRequest(HttpContext context)
 at ASP.default_aspx.ProcessRequest(HttpContext context)
 at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
 at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

make string parameter nullable like (string name=""). it is lptiona