@articlestack
According to the trac revision log you added a new directory under your root with the same name as the plugin. It looks like your whole root directory got copied to the new directory because it contains all the tagged versions and trunk. The plugin bot will not be able to find your newly tagged version unless it’s in trunk or the new version is tagged in root/tags.
You can fix it by moving 5.5 back into the root tags dir.
my-local-dir/$ svn cp amty-thumb-recent-post/trunk tags/5.5
then delete the extra dir
my-local-dir/$ svn del ampty-thumb-recent-post
and check it back in
my-local-dir/$ svn ci -m "tagging version 5.5"
