Frequently, when I click on a file to open it I get the error message below. It may be from any app - CAD, iWorks, OpenOffice, iPhoto. Sometimes I am inside the app, such as Keynote and use Open Recent Files, such as the example in the picture.
When I click on the file the second time, it usually opens. Sometimes the app opens, but not the file (blank screen). Another Open command then works. This has happend on the original motherboard and a brand new replacement board (same HD).
Pro, Mac OS X (10.7.3), I7, 8GB, 750GB, Lion