First, thanks for your patience in helping me solve this. It will make the plugin better and therefore help all users. This info definitely helps. Here’s what I think are the next steps:
1. Reset you permalinks. Set them to anything. Save. Then reset them to post name. I think you’ve done that, but this is important. It’s worth a double check.
2. I think you are on track, something with the remnants of the free version is causing problems. I’ve got to check that out, but unless a light bulb goes on quickly, (I’m going to take a quick look at my test site DB) I think that either:
(a) I’m going to have to send you a script that cleans out ALL the data from the free version, and maybe the data from the premium version, just to make sure. Or,
(b) One of us will have to go into the WP database and clean out that data using PhPAdmin.
Option (a) is probably safer, but it will take me awhile to get to it. Option(b) is faster, but much more dangerous.
In either case, I would suggest that you deactivate and delete BOTH plugins. And, most importantly, create a good backup of your entire site – DB & files. I haven’t destroyed an installation yet, but I won’t lie to you, it is possible whenever one starts making changes in PhPAdmin.
-Mark