Semantic Error (SEM1027): A program organization unit with the name '...' does already exist.

POU names must be unique within a project. In your project, two POUs with the same name exist

either in a subfolder of the folder 'COMPONENTS | Programming > Local > 'Functions & Function Blocks' or 'Programs'.
or in a referenced library ('Libraries' folder). This also includes POUs contained in firmware libraries (including the IEC 61131 standard library).