03.18.09 22:58:19 sapien pc 01.00.00.0609 ----------------------------------------------
03.18.09 22:58:19 reference function: _write_to_error_file
03.18.09 22:58:19 reference address: 401b13
03.18.09 22:58:19 Couldn't read map file './sapienbeta.map'
03.18.09 22:58:19 CreateDevice succeeded with refresh rate = 0
03.18.09 22:58:19 Increasing sound decompression buffer size to 1048576 bytes
03.18.09 22:58:20 the meter definition ui\hud\cyborg shield does not specify a stencil bitmap group.
03.18.09 22:58:20 the meter definition ui\hud\cyborg body does not specify a stencil bitmap group.
03.18.09 22:58:20 WARNING: 11 clusters in structure_bsp levels\test\deathisland\deathisland have no background sound or sound environment.
03.18.09 22:58:20 EAX: 0xFFFFFFFE
03.18.09 22:58:20 EBX: 0x00000101
03.18.09 22:58:20 ECX: 0x0013E408
03.18.09 22:58:20 EDX: 0x000002CC
03.18.09 22:58:20 EDI: 0x0013E408
03.18.09 22:58:20 ESI: 0x00000000
03.18.09 22:58:20 EBP: 0x0013E2E0
03.18.09 22:58:20 ESP: 0x0013E2D0
03.18.09 22:58:20 EIP: 0x7C90EB94, C3 8D A4 24 ?????
03.18.09 22:58:20 EXCEPTION halt in \halopc\haloce\source\tag_files\tag_groups.c,#3157: #-1 is not a valid object_function_block index in [#0,#4)

Any idea how to fix?

I would keep undoing whatever you did before you started sapien, Its how i find my errors and it works quite well.

I can't open the scenario.

Remove corrupted stuff in Guerilla if Sapien can't open.