Well, since you haven't gotten a response, I'll give it a shot. I was having this problem using the Tobacco Sky GDM Login theme in Linux Mint 13 MATE Desktop. I had tweaked it to run with MDM. After an update (? backport sources added),the theme no longer worked. Tonight I downloaded the original, untweaked GDM Tobacco Sky theme and installed it. It installed without problems and I'm using it again. Hopefully for Cinnamon also, the solution is to install the unaltered theme.
Last edited by yaye
on Mon Dec 24, 2012 5:28 pm, edited 1 time in total.
Unregistered Desktop Linux User since 1998 (Redhat 5.0 "Hurricane").