Index: modules/ssl/ssl_engine_init.c
===================================================================
--- modules/ssl/ssl_engine_init.c	(revision 1565929)
+++ modules/ssl/ssl_engine_init.c	(working copy)
@@ -914,9 +914,11 @@ static apr_status_t ssl_init_server_certs(server_r
         }
 
         /* and second, the private key */
-        keyfile = APR_ARRAY_IDX(mctx->pks->key_files, i, const char *);
-        if (keyfile == NULL)
+        if (i < (mctx->pks->key_files->nelts - 1)) {
+            keyfile = APR_ARRAY_IDX(mctx->pks->key_files, i, const char *);
+        } else {
             keyfile = certfile;
+        }
 
         ERR_clear_error();