diff --git a/icinga-build-upload-aptly b/icinga-build-upload-aptly
index 731331fc91e17516ba84b6ea5e8cc9421d88bfcf..52b698a184fcc057f337836b434710f51948301a 100755
--- a/icinga-build-upload-aptly
+++ b/icinga-build-upload-aptly
@@ -46,11 +46,11 @@ def detect_deb(path):
     if len(source) == 0:
         return []
     elif len(source) != 1:
-        raise StandardError, 'There more than one source DSC in ' + path
+        raise StandardError, "There more than one source DSC in %s" % path
 
     files = source + tarballs + changes + debs
     if len(files) < 2:
-        raise StandardError, 'There should be at least 2 files in ' + path
+        raise StandardError, "There should be at least 2 files in %s" % path
 
     return files
 
diff --git a/icinga-build-upload-aptly-subscription b/icinga-build-upload-aptly-subscription
index 7af00e1659d17fb4aa1dc05e11d24cb433a8e398..ec6ea832a774301c695b8ce41f5371da3d065830 100755
--- a/icinga-build-upload-aptly-subscription
+++ b/icinga-build-upload-aptly-subscription
@@ -46,11 +46,11 @@ def detect_deb(path):
     if len(source) == 0:
         return []
     elif len(source) != 1:
-        raise StandardError, 'There more than one source DSC in ' + path
+        raise StandardError, "There more than one source DSC in %s" % path
 
     files = source + tarballs + changes + debs
     if len(files) < 2:
-        raise StandardError, 'There should be at least 2 files in ' + path
+        raise StandardError, "There should be at least 2 files in %s" % path
 
     return files