SAMI is b*ll sh*t. After sometimes using it my game goes - bye bye!
Download - Alci's IMG Editor 1.5
Then open your gta3.img and there will be command (in the tool) - import (remove if exists) and import all of your (txd & dff) files. Then rebuild you gta3.img .
PS. I recomend to copy your gta3.img if you have enough space on your HDD, because after lots of rebuilding your gta3.img can crash and you wont get it back.
:bicycle: - like this ".gif "