diff --git a/src/server/slavefuncs.c b/src/server/slavefuncs.c
--- a/src/server/slavefuncs.c
+++ b/src/server/slavefuncs.c
@@ -809,8 +809,14 @@ int slaveBenchmark(char *datadir, int *b
   size_t readlen;
 
   ret = execio_open(&testrem, command, cmd);
+  if(ret)
+    {
+      fprintf(stderr, "Error executing blender\n");
+      return 1;
+    }
+
   buf[19] = '\0';
-  while(!execio_read(testrem, buf, 20, &readlen))
+  while(!execio_read(testrem, buf, 19, &readlen))
     {
       if(readlen > 20) {
         fprintf(stderr, "Something is terribly wrong!\n");