Within Deployment Manager we can schedule using frequency of 'Once'. Using other frequencies (Daily or Weekly) causes the error above when saving the schedule.
The direct cause is not known. However, in each case, multiple instances of Deployment Manager existed in different install paths or once existed and were not cleaned up entirely.
What has corrected this issue is simply Uninstalling Deployment Manager via Add/Remove Programs and cleaning up remaining Deployment Manager objects.
NOTE: Steps that may be needed after removing and installing Deployment manager.
1) Content Servers will need to be redefined again within the newly installed Deployment Manager
2) If using security certificates, after installing Deployment Manager, the Certificate will have to be applied again prior to connecting to the Collaboration and Deployment Services Server.
Removing Deployment Manager:
1) Uninstall Deployment Manager through Add and Remove Programs
2) Remove Deployment Manager cache (location OS dependent). Where the directory \Deployment Manager exists within the structure defined below, can be removed or renamed if you are uncertain.
C:\Documents and Settings\<user>\Application Data\SPSSInc\Deployment Manager
C:\Documents and Settings\<user>\Application Data\IBM\SPSS\Deployment Manager
3) Remove the remainder of the Deployment Manager installation directory left behind from Add/Remove programs.
By default this is:
4) Install Deployment Manager