Video clips in Event & Project went black, No audio/video. FCPX 10.1.1, Mavericks 10.9.1, Late 2013 27" iMac

I will try to put as much info as I can in the hopes that someone can help me solve my issue. Disclaimer: I am a relative novice with FCPX; I was more familiar with FCP express a few years back. Chances are, I am missing something relatively minor so please try not to beat me too harshly in the comments/replies haha.

I keep all of my FCPX files (aside from the application itself) stored on a portable external drive. I was working on a project on my Mid-2009 13" MacBook Pro (the computer I used to initially upload the media and create the project) and by accident I hit the USB cord, improperly ejecting the drive while working on the project. I was forced to force quit FCPX because the beach ball kept spinning for hours. When I restarted FCPX, the project was now missing, there was a small yellow exclamation sign next to the event but all of the media was still inside the event and working (audio and video).

After a few hours of trying to figure out how to get back the project I had spent 15-20 hours worth of work on and reading several blogs and forums, I opened a backup (the automatic backups FCPX does every 15-20 mins) library up from before I had improperly ejected the drive. However, I now did this on a new late 2013 27" iMac, not the original 13" Mid-2009 MacBook Pro (but remember, everything was stored on the external, not the internal hard drives of either computer). The project was in there but all of the media had "Missing Proxy" signs with no audio/video. I copied the project into the original library and everything seemed to be back to normal. The project had all of the media (audio/video/images) connected and inserted into their original place. I closed the backup library and continued editing my project in the original library.

After a couple more hours of work, I went to preview what I had completed so far from the beginning of the project and I came across about a 1:30 section of my project that was now black (see attached image), all of which was sourced from one continuous 10 minute clip (shot on a Canon 60D DSLR) in the event, which also was now black (also visible in attached image). There was no audio/video in either the project or event when playing/scrubbing through these clips. They worked fine previously but now, no go. I tried closing FCPX, trashing the preferences and reopening FCPX to no avail. Any advice/recommendations would be greatly appreciated.

Lastly, here are the specific details of all of the hardware/software of the computers, external drive and cameras used to capture the media.

CAMERAS:

Canon 60D DSLR w/ RODE VideoMic Pro attached

64 GB iPhone 5S

GoPro Hero 3 Black Edition

COMPUTERS:

Mid-2009 13" MacBook Pro

Processor: 2.26 Ghz Intel Core 2 Duo

Memory: 4 GB 1067 MHz DDR3

Graphics: NVIDIA GeForce 9400M 256 MB

Software: OS X Mavericks 10.9.1

Late-2013 27" iMac

Processor: 3.5 GHz Intel Core i7

Memory: 16 GB 1600 MHz DDR3

Graphics: NVIDEO GeForce GTX 780M 4096 MB

Software: OS X Mavericks 10.9.1

EXTERNAL:

1 TB Seagate Backup Slim for Mac

Format: Mac OS Extended (journaled)

83.88 GB available