I did more research and found a solution.

"Fixing Linebreak Issue (From another member)"

First of all I would like to say thanks for making such a nice forum plug-in, it was a breeze to install and skin to fit the rest of the site. Unfortunately I've come across a bit of a dilemma with making the forum function. When posts are drafted, it shows any line breaks and extra lines you make via hitting enter, but when the actual post is made it strips them out, leaving all paragraphs right next to each other. I know chances are it is something to do with the way the wordpress theme is filtering content, but I'm not sure what to look for in order to fix it. I was using the Archimedes theme that was developed for the webcomic plug-in, but a few of the other themes I have tested have been doing the same thing.

Is there a way to fix this in the functions file, or are there any barebones themes that support the forum plug-in from the get go to build off of?

Here is the authors response:

You may need to adjust your theme's whitespace CSS values. Here's a good starting point: http://www.w3schools.com/css/pr_text_white-space.asp

***** I put these code at the top of my theme style.css file*****

<style>
p
{
white-space: pre-wrap;
}
</style>

I would be patient and wait to hear from the relevant forum. I don't know whether anyone else here is familiar with it (I'm not) but you will find that people are often reluctant to give advice over plugins. I hope you get your answer soon.