diff --git a/src/@dseries/mrdivide.m b/src/@dseries/mrdivide.m
index ca29a1b43732f98752b0eef078e4310800b713be..4bd43152f591283b550fa301267bf4f0f4121b8c 100644
--- a/src/@dseries/mrdivide.m
+++ b/src/@dseries/mrdivide.m
@@ -118,7 +118,7 @@ if isdseries(o) && isdseries(p)
     end
     q.data = bsxfun(@rdivide, o.data, p.data);
 else
-    error()
+    error('dseries::mrdivide: wrong inputs')
 end
 
 return % --*-- Unit tests --*--
diff --git a/src/@dseries/mtimes.m b/src/@dseries/mtimes.m
index d1edade9f9e8e96214c953d9294beeb5b679df22..282683974da48230ce22c57f7fbdcd9e9d20e35a 100644
--- a/src/@dseries/mtimes.m
+++ b/src/@dseries/mtimes.m
@@ -130,7 +130,7 @@ if isdseries(o) && isdseries(p)
     end
     q.data = bsxfun(@times, o.data, p.data);
 else
-    error()
+    error('dseries::mtimes: wrong inputs')
 end
 
 return % --*-- Unit tests --*--
diff --git a/src/@dseries/plus.m b/src/@dseries/plus.m
index 0b995df8aeb7e65bfccb5936a6c098c0d12c5f9d..2089559551f021a2777950aaafc0081961bc499b 100644
--- a/src/@dseries/plus.m
+++ b/src/@dseries/plus.m
@@ -139,7 +139,7 @@ if isdseries(o) && isdseries(p)
     end
     q.data = bsxfun(@plus,o.data,p.data);
 else
-    error()
+    error('dseries::plus: wrong inputs')
 end
 
 return % --*-- Unit tests --*--