First try to select the document corrupted from the list in the Start Page, right click on it and try "Open 'FileName' Without Data" just to see if you are able to save the document. Anyway, set your User preferences in the Settings menu to make a backup every certain number of minutes. I use the save before reload option as well and keep a few number of last instances, so you can recover the last copy of, say, yesterday.
Second, update your copy of QlikView to v9SR6, which corrects several bugs.
Finally, those "Internal Inconsistency" errors with a letter are just informative to catch some bugs but there is not a list of error codes. Check with QlikTech Support in any case.