diff --git a/fillpdf.module b/fillpdf.module
index fa0b62da7a19483cbb49044970ec84d51b9a16c8..c1866378b302cd9e4ed2adf3996db50442c3b613 100644
--- a/fillpdf.module
+++ b/fillpdf.module
@@ -2024,11 +2024,16 @@ function fillpdf_pdftk_check($pdftk_path = 'pdftk') {
   }
   $output = array();
   $status = NULL;
-  exec($pdftk_path, $output, $status);
+  exec($pdftk_path . ' --version', $output, $status);
+  $output = implode("\n", $output);
   // Check the exit status.
   if (in_array($status, array(126, 127))) {
     return FALSE;
   }
+  // Check if version output includes "pdftk".
+  elseif (!strpos($output, 'pdftk')) {
+    return FALSE;
+  }
   return TRUE;
 }