Sorry my fault I am not English ;-) // bookmarks.html is a file.
You possibly found another "new" bookmarks file (they are empty when they are new ).
You find the Firefox bookmarks.html
Firefox: %USERPROFILE%\Application Data\Mozilla\Firefox\Profiles[Profilname][random string].slt\bookmarks.html
source:
http://www.holgermetzger.de/pdl.html
You can compare this with K-Meleon default location.
K-Meleon: %USERPROFILE%\Application Data\K-Meleon\Profiles[Profilname][random string].slt\bookmarks.html
The first [Profilname] is normally default.
p. s. K-Meleon can have another place when You choose that on install / that is in his own directory. But most ppl on NT base windows do not choose that.