diff --git a/scripts/build-package-files.sh b/scripts/build-package-files.sh
index 7d08f3dc..2915fead 100755
--- a/scripts/build-package-files.sh
+++ b/scripts/build-package-files.sh
@@ -10,8 +10,9 @@ fi
 
 INFILE_PATH=${1}${INFILE_SUFFIX}
 
-if [ -e ${INFILE_PATH} ]; then
+if [ ! -e ${INFILE_PATH} ]; then
     echo "ERROR! Source file ${INFILE_PATH} missing."
+    exit 1
 fi
 
 if [ -e ${1} ]; then