I also am using Mint14, with LibreOffice 3.5.4.2. The default MyDocuments when I first looked was /home/carlDocuments Notice the missing forward slash? I selected that line, clicked Edit, and navigated to the correct folder in the dialog that came up. The first time when I did it, I closed the Options window by clicking the lower rightmost button without looking at it, and that turns out to be a Revert button, undoing the edit I had just made. Duh. So I went through the process again, and ended by the leftmost, the OK button. It stuck that time. Maybe you did the same?
Just as an aside, my last name is Krucke, back a couple generations the U used to have an umlaut, (which I understand some people use "ue" as a substitute for) and I have a brother named Kurt. I saw your nickname "kkr..." before i even saw the question, and was thinking ha ha, that's my brother, then when you showed with the path that your name was Kurt also... Small world!
On Dec 10th 2012, this problem was reported as bug #1088488.
Hi @kkruecke, fdo#1088488 doesn't seem to be a valid id in the bug tracker. Do you know the correct bug id?