LiveCode Server: start session problem

[John Craig]

I decided to add some session code to my server project, but the 
following command causes an error on 6.6.1 on Linux (community and 
commercial);

start session

LC 6.6.2 had another problem, which is why I rolled back to 6.6.1. I've 
now also tried 6.6.0 and 6.5.2 - 'start session' also bombs those 
versions out.
Anyone know how far back I have to go to get a stable release with 
working sessions?