URL 301 redirect problem with Quick Page/Post Redirect Plugin

I’m using the Quick Page/Post Redirect Plugin.

Problem:
When redirecting URLs from my old site to my new WordPress based site it works as long as I don’t redirect the category page containing all those sub pages. Example: old URL /topicone.php?sid=00174 redirected to http://www.mydomain.com/topicone/ works fine. However, redirecting the old page /topicone.php to http://www.mydomain.com/topicone/ makes all sub pages (/topicone/post-name1 etc.) redirect to http://www.domain.com/topicone/.

Also, I want my URLs to look like this: http://www.domain.com/post-name/ but at the moment that page redirects to http://www.domain.com/topicone/post-name/

Kind of a challenging problem! Please help if you can.
Any suggestions to what the problem might be?