The problem I had was using command line special characters in my database passwords, in this case it was a semicolon (;). exec() then thought I was issuing 2 commands and was saying something along the lines of "sh: name of db: not found." So I think there needs to be some additional checking. First we need to find out if the exec worked in the way you intended it to. In this case check to see if !empty($table_list) around line 79.

Also dbscripts.module:1792 needs to be changed to 

if ($db[$pos]) $output .= ($arg? " -$arg":' ') . "'".urldecode($db[$pos])."'";

Hope this helps someone out. Took me a bit to figure out what was going on cause it happened under two different development configurations.