Just thought I'd let you know in case it helps. Have tried to get this going many times in the past and given up. Previously I could not change what was in the slots (see above posts). Tried again today and got the slot assignment working by changing the Javascript permissions. (firefox: Tools> Options > content> enable Javascript> Advanced). Turned on all the permissions and the slot assignment started working. Have now tried turning them all off one by one to see which specific permission was the culprit but now, even with them all turned off, its still works. So, I'm no closer to solving the mystery but at least I can use mojocafe again.