I use RHEL 6 as my regular operating system and for one of my user accounts I made one of the desktop panels as auto-hide and other as a fixed panel. I expected the hidden panel to appear above the fixed panel but was surprised to see a clash of both the panels in the same space (bottom). This has caused me to not get the session at all as the clash between the panels does not stop. However, if I could somhow use the terminal from another user account to change the properties of one of the desktop panels, it would solve the problem.
If you renamed your panel, change
<entry name="orientation" mtime="1356417211" type="string"> <stringvalue>bottom</stringvalue> </entry>