My computer's specs are:
Windows XP SP3 32-bit or Windows 7 SP1 64-bit,
Premiere Pro CS3 or Premiere Pro CS 5.5 (I get the same errors on both OS's, on both versions of Premiere with the same project)
Intel Core 2 Quad Q8200
My project specs are:
1080i project - video only - no effects added
The footage is 55,000 JPG files at 1920x1080, no compression
Render settings are: 1080x1920 Microsoft AVI; Compressor: none
The footage is arranged into ~27 Bins each of 2000 JPG's
The project file is ~270 MB
What I did: After each 1-2 Bins dragged onto the Timeline, I would save the project just fine. All worked fine until I dragged the 6th Bin onto the Timeline and tried saving. Then I get one of the above errors.
The problem is that your system is woefully underspecced for such kind of editing. It would already be hard to edit SD DV with that length on such a system, but with this footage your are killing it. Even if you did not have PR throw up an error, chances are that exporting with those settings would take about a whole pregnancy, around 9 months.
The only solution I see is getting a new system that meets minimum requirements at least. Keep in mind that JPG's are pretty demanding, so your project will fall into the intermediate level at least. See Adobe Forums: System requirements for CS5 and Adobe Forums: What PC to build? An update...