diff --git a/src/Makefile.am b/src/Makefile.am
index 4e431c5..1079f0d 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -15,6 +15,7 @@ scyther_SOURCES = main.c \
 		 runs.c runs.h \
 		 modelchecker.c modelchecker.h \
 		 report.c report.h \
+		 error.c error.h \
 		 debug.c debug.h \
 		 mgu.c mgu.h \
 		 substitutions.c substitutions.h \