"Cannot complete request... Access violation occured"

[jonnyb8390]

Very strange... Here goes:
• While working within a session (about to print too! Damn you Murphy!), I noticed strange pops when the playhead passed the end of a region. Knowing that the region was a consolidated file with a fade, I attempted to delete the pop and draw a fade anyway when this error occurred for the first time.
• After working for a little bit checking the rest of the drums on the fadeout, Pro Tools only played back audio of one of my Kick drums. I had been going through and soloing to check and thought for sure that I must have left one on but no... Pro Tools went crazy on me.
• After some craziness, I closed the session and attempted to reopen it. At the very end after restoring audio files, activating inserts, reading fades etc., this message pops up again. Must be a corrupt file of some sort, right?
• I create a blank session called "Restore" and attempt to import the session data. Didn't think it would work but I had to try.
• I give up, I trash prefs/databases and open the previous "save as" version of my session and begin the process of re-doing all of my moves (volume automation mainly, with one new EQ plug-in and changes to 3 or 4 EQ's). Almost done when the same SH#@ starts happening again! Good thing I "Save As" as soon as I open. Just to check - other "Save As" versions still open fine.
• Now I reload my clean disk image of my system to remove that from the equation. I even perform maintenance on the external FW drive that I'm running from (including a BU), even though other sessions appear to open fine.
• Opening the previous "Save As" still works. Opening the corrupt file still generates the same message. How can I continue to mix without corrupting my new .ptf file?

I'm going to try mixing this for the final time. Hopefully someone can help. I need to get this done today.

Thanks for reading this really long, and boring post.

-Jon B.

-Update: The "Save As" file that was okay, is now giving me problems. Digi??? You out there???

-Another update: Xferd uncorrupted session to system drive and mixing off that. Encountered same symptoms - click at end of a region that should not be there - and a new one: could not create a fade. Using keyboard shortcut at first, then opened the dialog box. Preview worked and fade created in window was audible, however it would not apply that fade to the track. It gave me a "default" fade of predetermined length regardless of selection, and fade type was not the type entered in preferences.

MacPro 2x2.8 GHz Quad Intel
4GB RAM
OS 10.5.4
PT 7.4.2cs1
ProTools HD 2 System
w a 96i/o