I have the same problem (program stops when I use the possibility to add a comment in my timeline). I use Vegas for quite a long time. I put my question about this faillure of the program a couple of days ago, but until now I did not get any answer. Please help me.
This has already been done... without success, I think I have to uninstall the Windows packs (C++) that I installed when installing VP411, but I don't know which ones I don't and so much..
My other software is performing good. The problem exists since I installed VP20. I use Vegas all day with a project of almost 2 hours. Veg-file of about 7.800kB.