Your Avira could definitely well be causing the 0x50 errors. I would uninstall that and then install MSE as a replacement.
Your Intel storage filter drivers are out of date and need updating. Please visit Intel's website and let it scan to find the latest drivers and install.
Code:
iaStorV iaStorV.sys Wed Apr 08 12:57:17 2009
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These two things done should fix it for you. All your other drivers look well. If not, test memory as previously advised. Good luck.
This driver could be causing the crashes also:
Code:
GEARAspiWDM GEARAspiWDM.sys Mon May 18 08:17:04 2009
If you can't figure out the problem, then uninstall iTunes to test.