Please delete... my bad

Hi, I’m trying to movea project to Ember CLI. But I have build problems. If I save my CoffeeScript file, I get

Build successful - 7625ms.

Slowest Trees                  | Total          
-------------------------------+----------------
TreeMerger (vendor)            | 2003ms         
CustomReplace                  | 1162ms         
TreeMerger (appAndDependencies) | 649ms          
Concat: Test Support Suffix    | 623ms          

As soon as I refresh the web page, in the log appears:

EmberCLI::App::BuildError (EmberCLI app "frontend" has failed to build):
  Error: ENOENT: no such file or directory, lstat 'frontend/tmp/config_loader-tmp_cache_dir-aRzPdXMm.tmp'
      at Error (native)
      at Object.fs.lstatSync (fs.js:836:18)
      at symlink (frontend/node_modules/ember-cli/node_modules/symlink-or-copy/index.js:63:26)
      at Function.symlinkOrCopySync (frontend/node_modules/ember-cli/node_modules/symlink-or-copy/index.js:58:5)
      at frontend/node_modules/ember-cli/node_modules/broccoli-caching-writer/index.js:103:21
      at lib$rsvp$$internal$$tryCatch (frontend/node_modules/ember-cli/node_modules/promise-map-series/node_modules/rsvp/dist/rsvp.js:489:16)
      at lib$rsvp$$internal$$invokeCallback (frontend/node_modules/ember-cli/node_modules/promise-map-series/node_modules/rsvp/dist/rsvp.js:501:17)
      at lib$rsvp$$internal$$publish (frontend/node_modules/ember-cli/node_modules/promise-map-series/node_modules/rsvp/dist/rsvp.js:472:11)
      at lib$rsvp$asap$$flush (frontend/node_modules/ember-cli/node_modules/promise-map-series/node_modules/rsvp/dist/rsvp.js:1290:9)
      at process._tickCallback (node.js:350:11)

If I restart the server, everything is OK again. Thanks to the experts, I honestly dont have a clue about this error…