[HELP} Studio generate false NavMesh format

[RedScar75]

hey guys,
(i use ISS source)
if I want to build navmesh I get only these files:
build_config.xml
Level.NavGenProj
level.obj

If I want to start the server it crashs:

000001.139| TERRAIN: LOADING Levels\cn_stress\TERRAIN
000001.144| TERRAIN3: Finished reading script file
000001.180| TERRAIN: LOADED
000001.973| Loading 'Levels\cn_stress\collections\collections.xml'
000001.973| r3dFile: can't open Levels\cn_stress\collections\elements.bin
000001.973| COLLECTIONS: Could not open 'Levels\cn_stress\collections\elements.bin'
000001.973| NavMesh.Load...
000001.977| !!! ERROR: failed to load navdata Levels\cn_stress\navigation\autodesk/level.NavData : 0

000001.978| !!! crashed, thread 92576
000001.978| Creating minidump at logss\GS_1000005e932e9.dmp
000002.285| Minidump created.

[MentaL]