diff --git a/src/util-io.scm b/src/util-io.scm
index 8b25167..51ccf58 100644
--- a/src/util-io.scm
+++ b/src/util-io.scm
@@ -36,7 +36,8 @@
  (import scheme
 	 (chicken base)
 	 (chicken io)
-	 (chicken process))
+	 (chicken process)
+	 (chicken format))
 
  ;; If given string begins with UTF-8 BOM, it is removed.
  (define (remove-optional-bom str)
@@ -59,7 +60,11 @@
  ;; Very simple shell command wrapper that returns lines produced by
  ;; given command. Dangerous - performs no argument escaping!
  (define (get-process-output-lines cmd . args)
-   (let-values (((stdout stdin pid stderr) (process* cmd args)))
+   (let-values (((stdout stdin pid stderr)
+		 (process* cmd
+			   (map (lambda (x)
+				  (format "~A" x))
+				args))))
      (close-output-port stdin)
      (let ((result (read-lines stdout)))
        (let-values (((a b c) (process-wait pid)))