if its the memory read error im thinking of you can fearlessly ignore it........sometimes there will even be 2 of these errors. no one knows what it affects, and it doesnt seem to harm anything so dont worry.
in 1.6 we could use a spot_light instead of light_environment........in source go back to the light_environment only.
the ambient light part of this entity, which is new, is actually an adjustment to the shadow color. theres also a shadow_ control point entity.
DO NOT use light_dynamic unless you want serious FPS problems. this engine is not yet ready for dynamic lighting.
its makes no sense that you dont get lightmaps with an env_sun because its actually a dynamic sprite and is NOT light
so add the light_env.....adjust the PITCH to something between -45 and -90 to begin seeing shadows.......its default is -90 which is pointing the light straight down.....-60 is nice for testing. and choose a horizontal shine direction with the YAW (black circle)(its in relation to the TOP view of the 2d grids in hammer.
you can leave your env_sun in there.
hope that helped somewhat