Fixed.

diff --git a/testing/copy/desktop/home/plom/.plomlib/prefixed_msg b/testing/copy/desktop/home/plom/.plomlib/prefixed_msg
new file mode 120000 (symlink)
index 0000000..42ff428
--- /dev/null
+++ b/testing/copy/desktop/home/plom/.plomlib/prefixed_msg
@@ -0,0 +1 @@
+../../../../../scripts/lib/prefixed_msg
\ No newline at end of file