I think I got it working now.
I uninstalled Pelles C and installed it again. (Just to have a clean install, but it doesn't resolved the problem.)
I deleted sysdefs.tag and then I created a project and builded the program.
It works now!
I now realized that the info to show code completion is build to this file and it needs to create some kind of cache before using it.
Now, I feel comfortable enough to work with Pelles C. I have been growing up my knowledge on C, win32api and DOS assembly/win32 assembly.
Now I'll work on some snipets, utilities and tutorials on C programming with Pelles C and Win32API, and also some win32asm with FASM.
But I need some free web hosting, because I'm going to create a page to store my work and share it with other people and also help newbies.
Do you know some good and free web hosting for simple HTML page only? (no need for php, cgi, and other things)
Thanks!