Black screen

Hi
I made a test level using A6 template . After 90 secs I get a black screen, ... I can hear sounds(player walking).
If I dont charge the gun ( key "E" ) I can play only 180 secs, and I get also a black screen. A bug ?
I have test levels using old templates, and them work fine.
Some help will be great.
Thanks

A6 com 6.31.4
xp home
Nvidia Geforce Fx 5200 (DUAL SCREEN)
screen 1024 x 768 75 hz max. No screen saver.

HI AGAIN,
I FOUND THE PROBLEM : I JUST ADDED TO THE HEAD OF THE SCRYPT THIS :
-var video_mode = 8;// 1024x768
-var video_depth = 32;// D3D, 32 bit resolution
-var video_screen = 1;
IT'S NORMAL THAT A6 DONT CREATE THIS BY DEFAULT, OR FORGHET I TO ADD A SCRYPT ?
CHEERS, MAXIMO

There can be many reasons for a black screen, however when it happens after 90 seconds, it's not likely a DirectX or video resolution issue. Maybe you're getting stuck in a wall after 90 seconds, or something like that.