BOXPUP - ROX - symlink not executing

[luc_jj]

(quite new newbie to linux)
hi,
2 symlinks located in a shortcut folder of the ROX side pane (index pane?) have a different behavior:
link-to-firefox-bin does nothing but is ok in the "my-applications/firefox" folder.
a similar symlink for seamonkey works correctly in the same side pane shortcut folder:
link-to-seamonkey-bin is ok

Where to investigate?
Thanks in advance