If you cannot delete or modify a static load case with the following error message "[Error] The Load Combination Name =""..."" contains errors," it is because one or more static load cases that you are trying to delete are used in defining the load combination(s).
In the example case shown below, there are three load cases defined, Tendon, Dead and Superimposed Dead Load. When the [Modify] or [Delete] function is used on any of the load cases, the program shows an message as: "[Error] The load combination name = ""Service III" contains errors."
If you check the load combination accordingly, you can notice that the corresponding load cases are used for defining the load combination(s).
After you delete or modify the load combinations or the load case from the load combination, you can delete or modify the static load cases without any problem.