My plugin works only when there is a page not found error.
It then does a look-up on the database for a similar page and redirects to it.
It does not change the permalink structure. It does not change the .htaccess file.
I think you may have installed another permalink plugin. Is this possible?
Using FTP, go into the plugins folder under content and delete the permalink-finder-plugin folder if it exists, just to make sure that things are completely clear.
You can reset the permalinks by going into settings and then clicking permalinks. You can then change the permalink structure to something and save. And then put it back the way you want it and save. This will reset the permalink structure back the way you want it. This is completely done by wordpress and you don't need a plugin to do it.