Sequence Diagram - models, fragments, and notes all became NULL suddenly

I already submitted a bug report with the same subject line, see who can help me out first.

here is the ticket ID: CVT-292969

In the project I am working on, all of the sudden, in some of my sequence
diagrams, all models/combined fragments/etc (including notes!) are suddenly become empty.

i have uploaded my screenshot to the following URL if you want to take a look.

compare untitled3.jpg with untitled4.jpg, u see that the tools column in untitled4 (i circled it with red) doesn’t not exist in the untitled3 too.

i also found few *.vpp.corrupted files but I am not sure if they are related, they are being attached.

please help, i need the diagrams recovered if possible; if not, i still at least need a fix to make sure something like that won’t happen again.

i am using VP standard edition 6.0 Build sp1_20070302

Mike Lau