Open VIETNAMSEA_data.ini and scroll down until you see this.....
[Texture001]
Filename=vietnamS1.TGA
HasWater=1
HeightMap=vietnamS1_hm.BMP
HeightMapScale=3.000000------- This number could be anything!
Color=0.114571,0.204605,0.305404
SolidObjectTexture=
AlphaObjectTexture=
Change whatever the number in the "HeightMapScale=" is to "0"
Do this for all [Texturexxx] entries! An easy way if you use notepad (should be notepad by default), is to select edit, then replace, then type or copy "HeightMapScale=x.xxxxxxxxx" line into both boxes, and change the number in the bottom box to "0". Then select "Replace All"
This worked for me, I hope it works for you