phpBB WordPress integration: config.php not found

I’m trying to set up the bridge between WordPress and phpBB, and so far it’s been going well, but after I install the WP-United bridge MOD, the WordPress plugin throws the following error

ERROR: phpBB’s config.php could not be found at the location you chose

There should be a selector, allowing my to browse directories, but for some reason there is non on my computer. Instead I get the following message

WP-United needs to know where phpBB is installed on your server. Find and select your phpBB’s config.php below.

Path selected: Not selected

Unlike what was mentioned in other posts on the subject, there is also no entry form that would allow me to enter the path directly.

Can someone please tell me how I can get wp-unite to go back to its initial state and ask me for the path? Or is there a way I could hard-code it?

Any ideas or suggestions would be most appreciated, because I’m quite stuck at this time.

Thanks so much!