imovie / idvd freezes (not responding)

I am having a hard time with imovie and idvd.

I am trying to make home movies from my video camera. I import everything fine. I build the project, adding all of my clips in their entirety. I place title cards for the dates/events. I then place chapter tags for exporting to imovie. My current family movie is about one hour and 15 minutes long. Hre is where I'm getting really frustrated: when I share to idvd, it takes a long time to process. I usually begin this process before I go to sleep, then wake up in the middle of the night to see what the progress is. Most of the time, imovie ends up freezing (not responding). I have to force quit, and restart the machine — restarting by forcing it to shut off by pressing and holding the power button. All of my video files are stored on a Seagate Free Agent GoFlex 2TB external hard drive. I have tried clearing out all files from my hard drive, giving me approximately 74 GB of available space on the hard drive. By doing this, I was able to process my movie to idvd, but now idvd is freezing (not repsonding) when it boots up.

Even when I make a short movie (a 1.5 minute video of my daughter's class project), when exporting to idiv, it exports fine and relatively quickly,m but idvd freezes upon startup.

It frustrates me, because I was able to do this fairly easily with imovie 6.0. My digital 8 video camera died, so I bought a Sony HD digital handycam video camera, which forced me to upgrade to mac OSx 10.6 so imovie vould read the camera for importing.

Is it a RAM/Hardware issue?

Is it the external Hard Drive issue?

Is it imovie or idvd?

I would really like to get this figured out. Any help would be appreciated.

Here is my system info:

Model Name: iMac
Model Identifier: iMac4,1
Processor Name: Intel Core Duo
Processor Speed: 1.83 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 2 MB
Memory: 1.5 GB
Bus Speed: 667 MHz
Boot ROM Version: IM41.0055.B08
SMC Version (system): 1.1f5

Memory Slots:

ECC: Disabled

BANK 0/DIMM0:

Size: 512 MB
Type: DDR2 SDRAM
Speed: 667 MHz
Status: OK
Manufacturer: 0xAD00000000000000
Part Number: 0x48594D503536345336344250362D59352020
Serial Number: 0x00001152

BANK 1/DIMM1:

Size: 1 GB
Type: DDR2 SDRAM
Speed: 667 MHz
Status: OK
Manufacturer: 0x2C00000000000000
Part Number: 0x3848544631323836344844592D3636374531
Serial Number: 0xDD28DC5B