Index: /trunk/src/org/openstreetmap/josm/data/validation/tests/MapCSSTagChecker.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/validation/tests/MapCSSTagChecker.java	(revision 7233)
+++ /trunk/src/org/openstreetmap/josm/data/validation/tests/MapCSSTagChecker.java	(revision 7234)
@@ -337,5 +337,5 @@
                 try {
                     m.appendReplacement(sb, String.valueOf(argument));
-                } catch (IndexOutOfBoundsException e) {
+                } catch (IndexOutOfBoundsException | IllegalArgumentException e) {
                     Main.error(tr("Unable to replace argument {0} in {1}: {2}", argument, sb, e.getMessage()));
                 }