Just wanted to share this information in case anyone else runs into this issue. After updating all of our servers to 7.5 SP1, one of the six started having issues adding targets or computers to Managed Software Deliveries, returning the error "The data could not be loaded."
Checking the Altiris Log Viewer, I saw an error along the lines of this (I've removed a lot of the extraneous SQL details)
Failed to save ResourceTarget Item save failed: 'computer list (1 item)' (guid) [Altiris.NS.Exceptions.AeXException @ Altiris.NS] at Altiris.NS.ItemManagement.Item.Save() at Altiris.NS.ItemManagement.Item.Create(Guid productGuid) at Altiris.NS.UI.DataProviders.ResourceGroupOpenSaveProvider.SaveObjectInternal(XmlDocument dataDocument) at Altiris.NS.UI.DataProviders.ResourceGroupOpenSaveProvider.SaveObject(XmlDocument dataDocument) Procedure or function spUpdateResourceTarget has too many arguments specified. SQL Exception details: code=8144, procedure=spUpdateResourceTarget
Checking the spUpdateResourceTarget stored procedure in the database and comparing it to a known working one, I found that somehow it was missing a section or two. To fix it, I grabbed a copy from a working NS and executed it in SQL Studio against the problematic database and the problem went away immediately, without even needing to restart services. Since the spUpdateResourceTarget stored procedure seems to be identical across multiple installs of the Symantec Management Platform, I've attached a known good copy to this post since I know not everyone has access to a second, working server.