--- a/src/dmzlib.c	Mon Mar 02 02:56:37 2015 +0200
+++ b/src/dmzlib.c	Mon Mar 02 03:09:10 2015 +0200
@@ -470,10 +470,16 @@
 
     // Build the code tables
     if ((ret = dmZLibBuildHuffmanTables(&ctx->zlength, codeLengths, hlit)) != DMERR_OK)
-        return ret;
+    {
+        return dmErrorDBG(DMERR_DATA_ERROR,
+            "Invalid literal/lengths set.\n");
+    }
 
     if ((ret = dmZLibBuildHuffmanTables(&ctx->zdistance, codeLengths + hlit, hdist)) != DMERR_OK)
-        return ret;
+    {
+        return dmErrorDBG(DMERR_DATA_ERROR,
+            "Invalid literal distances set.\n");
+    }
 
     return DMERR_OK;
 }