When I upload a file from the file manager, Concrete 5 gives me the following error:

An unknown error occurred while uploading the file. Please check file uploads are enabled That, and That your file does not Exceed the size of the post_max_size or upload_max_filesize variables.

File Uploads: 1
Max File Upload Size: 2M
Max Post Size: 8M

I've searched the forum this problem, modify php5.ini (did not work) and add the permissions using the dashboard (did not work)

Any help?