gnome-open debugging

[Guillermo Siliceo <guillermo siliceo gmail com>]

Hi, i'm trying to debug an odd behavior, gnome-open works if i login with an XFCE session but it doesnt if i login with GNOME, i get 
> cannot display 'filename.txt' "the location is not a folder"

And many programs show the same error, i've gone through many google pages trying all the GUI fixes but nothing works, so i'm resignated to read the code and see whats going on, where can i find the source for the binary i'm running? The ubuntu packages is huge and i'm not sure in what package is gnome-open.
Any help appreciated.