"Related Content" link in work flow Task form does not open in browser

Below is the step by step procedure for solving the issue

1.Open C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\template\layouts.
2. Locate the WrkTaskIP.aspx.  Make a copy of the file and Open in sharepoint designer.
3.  Locate the line SPHttpUtility.NoEncode(m_pageDescription,Response.Output); remove this and add below code 
<%
if(m_pageDescription.Contains(".xml"))
{
//Forcing any xml items to open with forms services
SPHttpUtility.NoEncode(m_pageDescription.Replace("http",SPContext.Current.Web.Url+"/_layouts/FormServer.aspx?DefaultItemOpen=1&ClientInstalled=true&Options=DisableSave&XmlLocation=http"),Response.Output);
}
else
{ 
SPHttpUtility.NoEncode(m_pageDescription,Response.Output);
}
%>
4. Do save

 hope this helps..