Index: src/org/openstreetmap/josm/plugins/PluginHandler.java
===================================================================
--- src/org/openstreetmap/josm/plugins/PluginHandler.java	(revision 4465)
+++ src/org/openstreetmap/josm/plugins/PluginHandler.java	(working copy)
@@ -383,7 +383,7 @@
                 parent,
                 tr("<html>Plugin {0} requires JOSM version {1}. The current JOSM version is {2}.<br>"
                         +"You have to update JOSM in order to use this plugin.</html>",
-                        plugin, requiredVersion, Version.getInstance().getVersion()
+                        plugin, Integer.toString(requiredVersion), Version.getInstance().getVersionString()
                 ),
                 tr("Warning"),
                 JOptionPane.WARNING_MESSAGE,
