Index: lams_central/src/java/org/lamsfoundation/lams/web/tag/HelpTag.java
===================================================================
diff -u -red0a9ce91d47d575397dbb3c8545a968a461bf49 -r9b0bf1af06d430bf42410223c72fd5670c1fcdb5
--- lams_central/src/java/org/lamsfoundation/lams/web/tag/HelpTag.java	(.../HelpTag.java)	(revision ed0a9ce91d47d575397dbb3c8545a968a461bf49)
+++ lams_central/src/java/org/lamsfoundation/lams/web/tag/HelpTag.java	(.../HelpTag.java)	(revision 9b0bf1af06d430bf42410223c72fd5670c1fcdb5)
@@ -23,6 +23,7 @@
 package org.lamsfoundation.lams.web.tag;
 
 import java.io.IOException;
+import java.lang.NullPointerException;
 import java.util.Locale;
 
 import javax.servlet.http.HttpServletRequest;
@@ -77,28 +78,39 @@
 		    
         	JspWriter writer = pageContext.getOut();
         	
-        	// retrieve help URL for tool
-        	ILamsToolService toolService = (ILamsToolService) getContext().getBean(AuthoringConstants.TOOL_SERVICE_BEAN_NAME);
-			IToolVO tool = toolService.getToolBySignature(toolSig);
-			
-			helpURL = tool.getHelpUrl();
-			
-			if(helpURL == null)
-				return SKIP_BODY;
-			
-			// construct link
-			
-			Locale locale = (Locale) session.getAttribute(LocaleFilter.PREFERRED_LOCALE_KEY);
-		    if ( locale != null ) {
-		    	language = locale.getLanguage();
-		    	country = locale.getCountry();
-		    }
-			
-		    fullURL = helpURL + module + "#" + toolSig + module + "-" + language + country;
-			writer.println("<div class='right-buttons'>");
-		    writer.println("<img src=\"" + Configuration.get(ConfigurationKeys.SERVER_URL) + "images/help.png\" onclick=\"window.open('" + fullURL + "', 'help')\"/>");
-		    writer.println("</div>");
-		    
+        	try {
+	        	// retrieve help URL for tool
+	        	ILamsToolService toolService = (ILamsToolService) getContext().getBean(AuthoringConstants.TOOL_SERVICE_BEAN_NAME);
+				IToolVO tool = toolService.getToolBySignature(toolSig);
+				
+				helpURL = tool.getHelpUrl();
+				
+				if(helpURL == null)
+					return SKIP_BODY;
+				
+				// construct link
+				
+				Locale locale = (Locale) session.getAttribute(LocaleFilter.PREFERRED_LOCALE_KEY);
+			    if ( locale != null ) {
+			    	language = locale.getLanguage();
+			    	country = locale.getCountry();
+			    }
+				
+			    fullURL = helpURL + module + "#" + toolSig + module + "-" + language + country;
+				writer.println("<div class='right-buttons'>");
+			    writer.println("<img src=\"" + Configuration.get(ConfigurationKeys.SERVER_URL) + "images/help.png\" border=\"0\" width=\"18\" height=\"18\" onclick=\"window.open('" + fullURL + "', 'help')\"/>");
+			    writer.println("</div>");
+			    
+        	} catch (NullPointerException npe) {
+    			log.error("HelpTag unable to write out due to NullPointerException. Most likely your Tool Signature was incorrect.", npe);
+    			// don't throw a JSPException as we want the system to still function.
+    
+    			writer.println("<div class='right-buttons'>");
+    			writer.println("<img src=\"" + Configuration.get(ConfigurationKeys.SERVER_URL) + "images/css/warning.gif\" border=\"0\" width=\"20\" height=\"20\"/>");
+    			writer.println("</div>");
+    			
+    		}
+        	
 		} catch (IOException e) {
 			log.error("HelpTag unable to write out due to IOException.", e);
 			// don't throw a JSPException as we want the system to still function.