Py script can not be registered correctly

I have downloaded several cvs builds for windows from www.blender.org. When I unzipped them to C:\WINDOWS\Desktop\blender-2.34-windows\ and update menus, all py files are presented, for example

Import {
'AC3D (.ac)...' 232 ac3d_import.py 0 'Import an AC3D (.ac) file.'
'LightWave (.lwo)...' 232 lightwave_import.py 0 'Import LightWave Object File Format (.lwo)'
'Motion Capture (.bvh)...' 232 bvh_import.py 0 'Import a (.bvh) motion capture file'
'Nendo (.ndo)...' 232 nendo_import.py 0 'Import Nendo Object File Format (.ndo)'
'Object File Format (.off)...' 232 off_import.py 0 'Import Object File Format (*.off)'
'Paths (.svg, .ps, .eps, .ai, Gimp)' 233 paths_import.py 0 'Import a path from any of a set of formats (still experimental)'
|_Gimp 1.0 - 1.2.5: Gimp_1_0
|_Gimp 2.0: Gimp_2_0
|_Illustrator (.ai) PS-Adobe-2.0: AI
|_InkScape (.svg): SVG
|_Postscript (.eps/.ps) PS-Adobe-2.0: EPS
'Pro Engineer (.slp)...' 232 slp_import.py 0 'Import Pro Engineer (.slp) File Format'
'Radiosity (.radio)...' 232 radiosity_import.py 0 'Import Radiosity File Format (.radio) with vertex colors'
'Raw Triangle (.raw)...' 232 raw_import.py 0 'Import Raw Triangle File Format (.raw)'
'TrueSpace (.cob)...' 232 truespace_import.py 0 'Import TrueSpace Object File Format (.cob)'
'Wavefront (.obj)...' 232 obj_import.py 0 'Load a Wavefront OBJ File'
'Wings3D (.wings)...' 232 wings_import.py 0 'Import Wings3D File Format (.wings)'
}

But When I use a fold like D:\orgc\windows\Desktop\blender\blender2.34\ and update menus, many scripts are missing:

Import {
'AC3D (.ac)...' 232 ac3d_import.py 0 'Import an AC3D (.ac) file.'
'Motion Capture (.bvh)...' 232 bvh_import.py 0 'Import a (.bvh) motion capture file'
}

How does this come? a bug?

I am using win98se. Thanx.