No harm, but you're using a theme that is not a part of the WordPress.org/extend/themes repository. This means the number of people who are familiar with your theme drops to insanely small numbers.
Also the best place to get help with a theme (or a plugin) that has it's own forum is on that forum. That's where people who use the theme hang out, and they're the folks best suited to answering your question.
This is also important because the people who made your theme are trying to make a living at WordPress and offer premium support (yes, for money). It's in everyone's best interest to spur the economy so they can make ends meet :)
With all that in consideration, there's no harm asking for WordPress help in the WordPress forum, but there's also no harm in being told that you're actually asking for theme specific help in a general forum, and you may be better suited asking that in the specific forum for that theme.
Make a post there, if you haven't already.
Even if I download the theme to poke at it for you, it's still going to be short of the support the people who made it can give you. My best advice for how to make the edit is to look at the index.php file for something like <?php the_excerpt(); ?> and change it. From there you should be able to make whatever change you want.