GarageBand's "Part of the song..." Error is Going Crazy

Hi. So I just recently replaced the HD of my modest 2006 macbook. The original one kicked the bucket. I'm not too savvy with hardware, but I was inclined enough to be able to replace it manually. It went off without a hitch, and here I am posting this thread on the thing. The new HD is apparently better than the one that came with this mac; twice as much drive space, also a slightly faster processor, if I recall.

Anyway, I'm a musician, and all my garageband project files are saved on an external HD. I used to run/work on these files directly from the external, and thats what I'm still doing now. For the past 48 hours since I installed the new internal HD, its been running smoothly. My low-end two year old mac is still capable of playing back 5-10 live instrument tracks with moderate effects on them without ever once having the ever-familiar "part of the song was not played" error popping up.

Ok this takes a bit of explaining, but my worst fear is that this just stems from a physically-induced technical error. Let me explain. I have a Seagate 250 G external, and the usb wire is slightly loose on the external's end (reminds me of when an audio-video wire starts loosening on a game system). That's always concerned me, but it hasn't seemed to have any effect on performance. Anyway, I had the macbook on the floor all day, sitting on the floor started hurting my back, and in the process of moving all the odds and ends on to my desk, I sort of forgot about properly removing the external and ended up making "improper device removal" happen like four times in 5 minutes.

After that I got a strange error that I should have remembered. Something about the audio not being able to play at all (the audio wouldn't play at all) and it had like a code number. It didn't happen again after I quit and then restarted garageband.

But now, since that moment, even on the simplest of projects, I'm getting the "part of the song was not played" error constantly. Every 5-10 seconds, in fact. It's killing me.

If anyone has any insight/ideas for what I should try doing, it'd be much appreciated.

 

It happened again.

"Error code -36 was returned by the core audio driver"

I had my mac evaluated by a professional computer store that was endorsed, officially, by Apple. They ran a "full diagnostic" that cost me 100 bones and told me that there was absolutely, no way in hell, anything else wrong with my machine.

...

Well this sucks.

(EDIT) Its looking like it is definitely the loose wire. When I gently attempt to nudge it back into place from its slight offness, it instantly shows the device removal error. I just spent 200 on this computer, and the most important accessory to it is now broken. I can't tell if it's the male piece (that is, the usb wire) or the female piece (that is, the external itself) that is loose, but I assume that if it's the latter that repair work on such a thing is nonexistent.

This seems more and more like it's becoming a hardware related question rather than a basic mac error. Move the thread if you like.

(EDIT #2) It still reads other files that exist on the external, like images, mp3s, text documents. It obviously lags when loading them though. It's like my external is existing in some netherworld of half-working files. Anyway, it can't be good, so I'm ejecting and leaving it be for now until I figure this out.