Thanks Dan,
Just to summarise. I turned on the ASPNET state service in order to use state server for session storage, once I'd sorted out serializing my own classes it then came up with the day pilot serialization errors.
I was using the release dll (5.6.1820) so I switched to building the day pilot project (same version) and this allowed me to add [Serializable] to the following classes.
Daypilot.Web.UI.ColumnColection.cs
Daypilot.Web.UI.ResourceCollection.cs
Daypilot.Web.UI.data.event.cs
Once I had rebuilt, the calendar and schedule control I'm using appear to work fine with all the tests I've carried out so far.
I'm not sure if this is the best way to fix the problem however it seems to work for now.
Hope this is of use,
Thanks
Darren