[f3_dl]

I don't know if the developer is still active so i post this fix for you.

If someone has the same problem as me with the table prefix go to /fmf/products/conversations/hooks/process_templates_complete.php and replace:

        SELECT c.conversationid AS conversationid, c.username AS fromusername, c.title AS title, 1 AS isconversation, c.last_message_dateline AS sortdateline
        FROM bmf_conversations_participant p
        INNER JOIN bmf_conversations_conversation c ON (c.conversationid = p.conversationid)
        INNER JOIN bmf_conversations_message m ON (m.messageid = c.last_message_id)

with

        SELECT c.conversationid AS conversationid, c.username AS fromusername, c.title AS title, 1 AS isconversation, c.last_message_dateline AS sortdateline
        FROM " .TABLE_PREFIX. "bmf_conversations_participant p
        INNER JOIN " .TABLE_PREFIX. "bmf_conversations_conversation c ON (c.conversationid = p.conversationid)
        INNER JOIN " .TABLE_PREFIX. "bmf_conversations_message m ON (m.messageid = c.last_message_id)

That should fix the issue.
I think they just forgot the prefix there - if there will be a new version i am sure that this will be fixed but if you are using 1.1 that should get rid of the prefix problem.