Import WP Filesize settings

anyone help me with this
i can’t upload big size with XML in WP even i change the PHP Configuration in Resource Limits to
Maximum memory allocation 128M
Maximum file upload siz 256M
Maximum input parsing time 60s
Maximum HTTP POST size 256M
Maximum execution time 30s
and stay in 2 MB in Import WordPress
but when i use Upload Filesize settings plugin they working but
i got this error when i Import XLM with 39mb
File is empty. Please upload something more substantial. This error could also be caused by uploads being disabled in your php.ini file or by post_max_size being defined as smaller than upload_max_filesize in php.ini.
how can fix this problem