Configuration Nightmare

I am really looking forward to getting your module working it is a great combination of features. However, I keep getting the same error for every permutation of config I have tried:

imap_open() [function.imap-open]: Couldn't open stream

My situation is:
I am using Drupal 5.10 and your latest rc release of convey.
I have set up a mailbox 'convey@mpcollab.org' on the same host account as Drupal is installed on.

I have tried the following settings for location:

{mail.mpcollab.org}convey
{/home/mpcollab/mail/mpcollab.org}convey
{/home/mpcollab/mail/mpcollab.org:993/imap/ssl}convey
{localhost:143/home/mpcollab/mail/mpcollab.org}convey

And many other permutations of the above at the suggestion of my hosts support line.

Could you suggest the appropriate settings for me to try given my situation and any other troubleshooting ideas to help resolve this.