That's the graphic engine..
Do you have any graphic card installed? Up to date?
Case yes, change the graphic engine, to do so right-click on your Tibia icon and select Properties. In the tab Shortcut, look for the line Target. Leave everything in this line as it is. Only at the end of the line leave a space, then add engine, leave another space and add 0 for DirectX 5.0, or 1 for OpenGL, or 2 for DirectX 9.0.
Hope it helps
..more than machinery we need humanity...