-600 error opening image files from the Finder when Gimp.app is open

[EnekoGotzon]

SOFTWARE

• Mac OS X 10.9.4 (13E28) –Mavericks.
  
• MacPorts base version: 2.3.1
  
• GIMP ports installed:
  gimp @2.8.10_0 (active)
  gimp-app @2.8.2_2 (active)
  gimp-help-en @2.8.1_0+python27 (active)
  gimp-jp2 @2.2.0_6 (active)
  gimp-lqr-plugin @0.7.2_0 (active)
  gimp2 @2.8.10_6+help_browser+python27 (active)
  
• All software up to date.
  
• "sudo port clean --all installed" command: executed.

ISSUE

Trying to open an image file with The GIMP from the contextual menu of the Finder:

• Always works if:
  .Both X11 and The GIMP are closed.
  .X11 is open and The GIMP is closed.
  
• Always fails if both X11 and The GIMP are open. Sometimes this error message is shown: The application “GIMP.app” can't be opened. -600.
  

Trying to open the same image files from the File menu inside the GIMP.app always work.

Thank you! :)

[EnekoGotzon]

Error message