Look, I deleted the wordpress installation and install again with the original wordpress (in english, the “lastest version”), and eveything works fine.
The problem is the “portugues wordpress” (pt.wordpress.org), this version doesn’t work the plugin installation, if I try the original wordpress in English (wordpress.org) this works normally.
I don’t know why, but to avoid problems and lost of time I will use the original wordpress in english and everything is allright!
Thanks for the attention and support, hugs! 😀
