Going under File->New->Models and documents, clicking "My documents" and then using the "parent folder" icon a couple of times crashes LibreOffice (tested with Writer and Calc). It could be when it goes out of the "Documents and settings" folder. I was able to test it and reproduce it under Windows XP. I don't have access to other OSes right away, but I should be able to verify on Linux and Windows 7 in the next couple of days. By the way, maybe I should open a different bug, but there is something going wrong under Models and documents. Everything responses very slowly. Since the window doesn't have a Windows' native look, I'm sure it is related.
Thanks for your report. Already reported as 'Bug 46249 - Applications abort while browsing file system'. Please create a new bug report for your second problem. [ http://wiki.documentfoundation.org/BugReport ] *** This bug has been marked as a duplicate of bug 46249 ***