Error in MTW need help!

[LH95]

Hi, I have the MTW Viking Invasion installed on my Windows 7. The game works perfectly. But when I enter a battle, the screen flashes and the vision does not move! Archiving has been created called "error" in the folder MTWVI written the following:
C: \ MedAddOn \ Crusaders_TW \ main3d_1.cpp (7050): DirectX call: E_FAIL (GENERIC)
C: \ MedAddOn \ Crusaders_TW \ main3d_1.cpp (1929): DirectX call: DDERR_SURFACELOST
C: \ MedAddOn \ Crusaders_TW \ BatleMap.cpp (646): DirectX call: DDERR_SURFACELOST

The settings of my computer are:
MS Windows 7 ultimated
AMD Athlon (tm) II X4 635 2.91GHz
RAM: 4G DDR2
Video Card: GForce 9500GT 1GB 16x OffBorad

Please if someone know the solution to my problem, I appreciate it.