This problem came after I tried to use the examples came with Lazarus ..
1. lazarus/examples/gridcelleditor/gridcelleditor.lpi
I love this example, it runs with no problem.
2. lazarus/examples/grid_semaphor/example/project1.lpi
I also love this example, it also runs with no problem.
3. After that I created a new project....
First I copied everything from number 1.
But I replaced TStringGrid1 with Semaphoregrid1.
There was such an error.
Please help.