Yeah, what version of Max? Also would help to show a screenshot of your material settings. What cubemap(s) are you using? Did you create them yourself, or use one of the ones that came with it?
Not sure what's causing your problem though. Is the normal map "normalized"? You can use the free Nvidia normal map filter in Photoshop to do this. http://wiki.polycount.net/PhotoshopTools#Actions.2C_Filters.2C_Scripts
What normalizing does is to prevent your normal map from going beyond regular values, preventing it from causing spikes or weird issues with your lighting.
Replies
Give us some details and screenshot without a diffuse map.
http://wiki.polycount.net/CubeMap
Not sure what's causing your problem though. Is the normal map "normalized"? You can use the free Nvidia normal map filter in Photoshop to do this.
http://wiki.polycount.net/PhotoshopTools#Actions.2C_Filters.2C_Scripts
What normalizing does is to prevent your normal map from going beyond regular values, preventing it from causing spikes or weird issues with your lighting.