             return unless key? # wierd error
             return unless key.indexOf(@prefix) is 0
             return if key in useful
-            @del_content key, (error) =>
-                @logger.error(error) 
+            @del_content(key)
+                .catch (error) => @logger.error(error) 
             return
         return

            if @hash_func(module_source) != module.hash
                @emit("ModuleDownloadFailed", event, module)
                return
            @set_content @make_key(module), module_source, (err, content) =>
                if err?
                    @emit("ModuleDownloadFailed", null, module, new DBError(module.url, err))
                    return
                module.source = module_source
                module.loaded = module.size
                @emit("ModuleDownloaded", module)
                @_reportTotalProgress()
                @_checkAllUpdated()
        module_request.onprogress = (event) =>
            module.loaded = event.loaded
            @emit("ModuleDownloadProgress", event, module)


        unless @emit("EvaluationStarted", @_current_manifest) is false
            @evaluate(@_current_manifest.modules)
                .then => @_cleanUp()

        return

