Contact your hosting company and ask them to set AllowOverride Options for your host.
I'm trying to upadate .htacess file with these parameters
php_value post_max_size 64M
php_value upload_max_filesize 64M
php_value max_file_uploads 128M
php_value max_input_vars 5000
but i'm getting a 500 Server Error,
Hello,
Sorry for the problem with the 500 error. Unfortunately, that particular error is very general. It could be caused by a number of things. We do have an article that might help with narrowing down and resolving the issue: 500 Internal Server Error.
If you have any further questions or comments, please let us know.
Kindest Regards,
Arnel C.