diff --git a/wp-db-backup.php b/wp-db-backup.php
index 2899e3b..c6ef619 100755
--- a/wp-db-backup.php
+++ b/wp-db-backup.php
@@ -1047,7 +1047,7 @@ function deliver_backup($filename = '', $delivery = 'http', $recipient = '', $lo
 			/**
 			 * Try gzipping with an external application
 			 */
-			if ( file_exists( $diskfile ) && ! file_exists( $gz_diskfile ) ) {
+			if (function_exists('exec') && file_exists( $diskfile ) && ! file_exists( $gz_diskfile ) ) {
 				@exec( "gzip $diskfile" );
 			}