iMovie (and iMac) does not recognize device(s)

Hello and thanks for reading. I know this topic is like beating a dead horse but this one is unique. I'm a professional editor and I couldn't figure this out so any help would be appreciated. Here's the play by play:

• I edit using FCP 5.1.4 and have for years. I've had the same set up running for years and do high volume editing.
• I have a chain of 4 Lacie drives, all connected by firewire.
• At the end of that string, I have my tape player for capturing footage, a Sony GV-HD700, which then goes on to the TVs, DVD players, etc.
• Also the end of that string, I also have a disc burner for making DVDs.
• So it goes: iMac > Lacie #1 > Lacie #2 > Lacie #3 > Lacie #4 > Sony tape player & DVD burner > TVs, VCRs, etc.
• Yesterday, I was in a rush and the DVD burner was going slow so I unplugged it from the end of the string of Lacie drives and plugged it directly into the back of the computer to see if it would burn faster.
• It didn't, so I plugged it back into the end of the Lacie string.
• At that point, Lacie #4 became unrecognizable to the computer and therefore so was the tape player, which is further down the chain.
• When I plugged the tape player high up the chain, into Lacie #3, it still was not recognized.
• I plugged the tape player (Sony GV-HD700) directly into the back of the computer...still not recognized.
• I took the Sony GV-HD700 into our other editing bay and it was still not recognized.
• I pulled out my camera (Sony HDR-FX1000) and plugged it directly into the back of the original computer...recognized just fine.
• I plugged Sony HDR-FX1000 camera into the back of Lacie #2...recognized just fine.
• I took the Sony HDR-FX1000 camera into our other editing bay...recognized just fine.
• I have a big deadline so I said "Screw it." and was just going to capture from the camera for the time being.
• I reset the Lacie drive chain, plugged the Camera into the back of Lacie #4 (just like the original setup) and BANG: Lacie #4 and the Sony HDR-FX1000 camera was not recognized.
• I plugged the Sony HDR-FX1000 camera directly into the back of the computer...still not recognized.
• I took the Sony HDR-FX1000 camera into our other editing bay...still not recognized.
• I thought it might be a Final Cut Pro issue so I pulled up iMovie and it does not recognize any device connected to the computer even though I'm looking directly at it plugged in.

The entire iMac has lost the ability to recognize devices that I've used for years. I've now lost the ability to capture footage and I'm running out of time. It's almost as if the devices were getting infected by one of the Lacie drives (I think Lacie #4). Is that even possible? Has anyone ever heard of something like this? I don't know if it's something I need to change on the iMac to recognize them again, or if it's a setting on the device to reset the connection, or if somehow the Lacie drive corrupted the devices and made them unrecognizable to iMacs.

It's very, very weird.

Thanks for your help.

27" iMac (2009)

OS X 10.8.5

Final Cut Pro 5.1.4

Tape player: Sony GV-HD700

Camera: Sony HDR-FX1000

I've had this setup for years so I don't know what type firewire it is.