(My post isn't showing up?) Sound effect muffles/is louder than the other audio layers

Question

I want to point out that the last time I posted this, the discussion was completely blank. This is a repost and hopefully it won't be blank this time
In my most recent short movie, I decided that I would focus a lot more on sound than I normally do, so bought a microphone, a recorder and a boom pole etc. I also decided to implement more sound effects (Bear in mind that I'm 16, not a professional).
Here's the video -  http://www.youtube.com/watch?v=qGkrFVZ0e5I (I think embedding the video was causing problems with posting)
Note that at about 0:10 seconds in, you can hear an alarm ringing, but also a sort of 'thump' sound (It's actually the sound of a vault opening/closing). You couldn't hear it normally, so I turned the bass up on it to 17dB. When playing it back in the timeline, it sounds perfectly fine, but when I export the video, much like the attached one, it's muffled and you can't hear the alarm or anything else.
Unfortunately I didn't have time to try and fix it, also that scene takes a while to export so I couldn't quite do any trial and error.
Now however, I'm going to enter the video into a small competition, so I thought I'd try and fix it...because it does sound terrible/unprofessional.
Any suggestions? Remember, it sounds perfect (In my opinion) when playing it back in the timeline. I'm using Premiere Pro CS5.5 on an 11,2 (October 2010) iMac running Mac OSX Snow Leopard 10.6.8, it's also being exported to a G-Drive FireWire 800 hard drive, not a RAID, perhaps that could be a problem?

Answer 1

"One thing which is realistically within your reach at this time and could really help you on future projects is if you can come up with some sort of beginning, middle and end"
That's one of the problems, people kept saying "Oh, this line's too long..." and shortnening it, and like Jim said "If you can't fire people, you're at their mercy" so I can't exactly deduct pay or anything...because they're not being paid
They even started saying "Woah! We've completely changed the script! hahaha!". Just shows how little they actually cared. And the script really was changed, I would send you the script but I don't want to veer too far from the topic
"You may need to find some way to compensate them for their time though"
I was going to bring a box of Coca Cola, but I thought it would be a bit hard to carry around...and I was kind of glad I didn't because I don't feel they quite deserved it and they were already a bit hyper. Maybe it would have gone better if I did bring the Coke, but I'll definitely order some pizza next time.
"Just software."
Great software that is! I don't know where I'd be without the student discount.
Anyway let's get back to the question.
I glanced at this a bit - http://www.uaudio.com/blog/understanding-audio-phase/
And tried using the original MP3. It still didn't sound good.
I then tried exporting the sound on its own, with the bass, then imported it, but it still didn't sound as good.
I asked my friend (Who happens to also have the surname 'Curtis') and he said "just sounds to me like you have it so loud that it's clipping" and suggested that I "multitrack" it, basically layer several of them on top of each other, but that didn't work either.
He decided to add the bass in and fix the 'clipping'. It sounded good, but once imported, you could barely hear it, so I thought I'd try putting the bass up to 17dB like before...had the same problem. It seems to only sound nice/fitting with the 17dB bass...am I just going to have to turn it down and live with it?