This should not be a problem if Blender exports .obj to the same directory you later use when importing to SH3D.
Note that the .obj format can consist of two or more files. If in Blender you export to Wavefront/OBJ, you should see .obj,.mtl (on top in the export menu). Blender will then generate the two files. The .obj file links to the .mtl file - so they should be kept in the same directory. The .mtl file can again link to texture files which could be elsewhere or in same directory (you may need to study the .mtl file with a text editor to find missing files).
Problem solved:
Texture file must be at the same folder as obj file.
Before i had textures in d:\textures - folder.
In .mtl was :map_Kd d:\textures\texture.png - its correct path, but 3D Sweet Home not load textures.
I change d:\textures\texture1.png to texture1.png and copy .mtl and .obj file to d:\textures - now it's work fine.
Thank you for help.