Below is my code written in html homepage component, i need logged in user profile. 

<script src="/soap/ajax/28.0/connection.js" type="text/javascript"></script>
<script src="/soap/ajax/28.0/apex.js" type="text/javascript"></script>
<script type="text/javascript">
  setTimeout( function()
    {
     alert('entered in function'); 
     var userProfile = sforce.apex.execute("UserProfileName", "getLoggedInUserProfile", {});                       
     alert('userProfile'+userProfile); 
    if(userProfile != 'System Administrator')
    {
          var divObj = document.getElementsByClassName('bRelatedList');
          if(divObj != null){
          for(var i=0;i<divObj.length;i++)
          {
                var items = divObj[i].getElementsByTagName("a");
                if(items != null )
                {
                       for(var j=0;j<items.length;j++)
                       {
                              if(items[j].innerHTML=='Del')
                               {
                                   items[j].style.display = "none";
                               } 
                       }
                 }
         }  
   }
  alert('exit from function'); 
  }, 1000);
</scrip>

first alert is getting displayed but from apex execute statement it is not executing.

here UserProfileName is class and getLoggedInUserProfile is static webservice method. when i call this method from console it is executing. 

what is the wrong in my code i am not understanding why it is not calling the class ? please