When specifying parameters for queries in a SQLDataSource control, the error "Too Many Parameters" may be displayed despite having the correct number of parameters for the Update command, when the command is specified in "text" on the .aspx page itself. The parameters must be the same case as the field names and must be spelled exactly the same as the field names, but with a leading "@" sign. This affects the ability to update the columns with the "Edit" link.
For example, column agent_name requires @agent_name, not @AgentName.
Since the Query Builder requires that the parameters be filled in, this is an easy mistake to make as typically the parameters for a stored procedure do not need to be spelled exactly the same as field names. But when using the SQLDataSource control, magic occurs in the background to align the textbox values with the field names.