changed priority to HIGH

Yes - same here - Mac OS 10.6.6

Can anyone post their log.txt file after the crash occurs?

The data files are in different places depending on your OS:
on Windows XP at C:\Documents and Settings\All Users\Application Data\Foldit\
on Windows 7 and Vista at C:\ProgramData\Foldit\
on a Mac, Ctrl-click on the app and choose "Show Package Contents, then go to Contents/Resources
on Linux, is is the Foldit directory

Has anyone been able to load a solution without crashing?

This used to be a common occurrence, it felt like it was size related, since The Vanishing only happened with the big interface/mutable puzzles, but the last 2 interface puzzles behaved themselves, so it must be puzzle specific I'm guessing. Maybe it's the minirosetta_database disulphide call? Here's the business end of the log.txt, XP pro 2002, SP3.

Autosaved autosave-102459-989170.ir_solution.
Error reading upload_tmp_987291_1267385438.ir_solution; expected SOLN, got .

Error reading upload_tmp_987291_1267385438.ir_solution; expected SOLN, got .

loading solution as guide: 0031712997.ir_shared_solution.ir_solution

ERROR: base_ref_info->sidechain_locks.size() == sequence_mapping.from_reference().size1()
ERROR:: Exit from: ..\..\src\interactive\util\ReferencePoseInfo.cc line: 250

Old puzzle. Closing.