In Acquisition, you can only load methods that are consistent with the current Data Player instrument configuration.
For methods to be consistent, the path set in instrument configuration is essential (parameter Path to Signals). When you create and save a method, this path is saved within the method. When you load the method at a later point in time, the saved path must still match the path in the current instrument configuration. In addition, the corresponding folder must exist in the file system.
Relative and absolute paths are considered different, even if pointing to the same folder.