diff --git a/externals/Makefile.am b/externals/Makefile.am
index 06e8eedee0..854a652680 100644
--- a/externals/Makefile.am
+++ b/externals/Makefile.am
@@ -35,12 +35,12 @@ endif
 
 # CWI ATerm
 
-ATERM = aterm-2.4.2-fixes
+ATERM = aterm-2.4.2-fixes-r2
 
 $(ATERM).tar.bz2:
 	@echo "Nix requires the CWI ATerm library to build."
-	@echo "Please download version 2.4.2-fixes from"
-	@echo "  http://losser.st-lab.cs.uu.nl/~eelco/dist/aterm-2.4.2-fixes.tar.bz2"
+	@echo "Please download version 2.4.2-fixes-r2 from"
+	@echo "  http://losser.st-lab.cs.uu.nl/~eelco/dist/aterm-2.4.2-fixes-r2.tar.bz2"
 	@echo "and place it in the externals/ directory."
 	false