Hey there. Thought I’d just add my findings on this. First off great plugin, really like it very much.
I was having the same problem as the OP. I’m using 4.1.1 running the Bayside theme, pretty much straight out of the box. Running locally on PHP 5.5.19. MySQL is 5.6 – No Cache Plugin installed
Created a new RSS Feed, worked perfectly as it should, then Deleted all posts, then removed those posts from the Bin. Tried then to re-run the import and 0 posts imported. Tried removing and recreating the feed but still nothing.
Took at quick looking into the DB.
– Removed all records in wp_posts and rerun import (still nothing)
– Removed all records in wp_postmeta and rerun import (still nothing)
THEN – in the wp_options table there was a record called “rss_pi_imported_posts”, I removed this and voila I could re-import again 🙂
Hope this helps anyone ….