Added a note on getting 404 Not Found errors when loading the database.

Mac/OSXResources/app/Resources/English.lproj/Documentation/packman.html

@@ -35,8 +35,18 @@
 				you about this, and also about other external dependencies.</p>
 				
 				<p>PackageManager is available as a separate application and also
-				as a function of the IDE, through the File->Package Manager menu
+				as a function of the IDE, through the <tt>File->Package Manager</tt> menu
 				entry. </p>
+				
+				<h2>Troubleshooting</h2>
+				
+				<p>If package manager fails to open the database first check that you are
+				connected to the internet. If you are connected then the problem
+				could be that there is no database (yet?) for your version of Mac OS X.
+				In the standalone Package Manager you can open an alternative database
+				with the <tt>File->Open URL...</tt> command, but you should realize that
+				you are now on untested ground. </p>
+				
 			</td>
 		</tr>
 		</table>