Thanks!
The 8.3 trick worked, I changed "C:\Program files\CodeBlocks\wxWidgets-2.8.8" in "C:\PROGRA~1\CodeBlocks\wxWidgets-2.8.8", and now I can compile everything.
I'll also try with new MinGW releases, to see if new windres.exe no longer have this bug.
Last thing, can you confirm me that the path for #wx global variable MUST be an absolute path, and that relative path don't work (I mean relative with respect to codeblocks folder, like saying "./wxWidgets-2.8.8" instead of "C:\Program files\CodeBlocks\wxWidgets-2.8.8"), because when I do so I get errors not only related to windres.exe, but also gcc.exe