Sounds like you just need to manually attach the textures to your object; just load the OBJ, select it, and switch to Carrara's Texture Room by clicking the paintbrush icon in the upper left portion of your screen. Once you're in the texture room, just load the textures into the shader tree; for example: in the color channel, select "texture map" and click the load icon to navigate to the map you made in CS5. Rinse and repeat for any other maps you may have. (Bump, spec, etc.)
JT