ERROR The import process is …

When I try to import from joomla… it is stop on the begining.
this is the error and the log:

=== START import 2016-05-18 09:59:37 ===
[COUNT-TOTAL]277 elements to import
[COUNT]0 categories processed
0 categories imported
[ERROR] The import process is still running. Please wait before running it again.
=== END import 2016-05-18 09:59:39 ===

Pages and medias from pages are imported. But NOT imported 270 posts with his medias…
What is the problem¿?

thanks!

https://ww.wp.xz.cn/plugins/fg-joomla-to-wordpress/