This is an unfortunate bug, whereby some users have actually saved a "space" character as the title in a word or pdf Doc. What happens is, no link is displayed since, it is not smart enough to decipher that it is a space.
To accomodate browsers that can't underline spaces you can change them in the script. Either at walk time, before storing into the database, in dowalk or at search time in search.
<sandr "\space+" "" $Title><!-- see if all space -->
<if $ret eq ""><$Title=""></if><!-- yes, activate "no title" logic -->