I am running SQL Server 2008r2 SP1.
If you have a report with a multi select parameter that allows blanks, a blank label will either prevent you from setting up the subscription, or cause the subscription to fail when it is run.
Message: 'firstChild' is null or not an objectand the subscription error is:
Failure sending mail: Default value or value provided for the report parameter 'ReportParameter1' is not a valid value. Mail will not be resent.
I have opened an issue on Connect: http://connect.microsoft.com/SQLServer/feedback/details/750927/blank-parameter-labels-cause-error-in-subscriptions
What I have done in the meantime is to replace any blank labels with a holder character ("-").
Has anyone else ran into this issue?