fixed version tested and runs in DCS now

compiler/src/ScriptCompiler.ts

@@ -65,6 +65,16 @@ export class ScriptCompiler {
                 const luaFile = LuaFile.createFromFile(fullPath, this.options.onError);
                 const luaReference = fileReferenceToLuaVariable(relativePath);
                 const key = luaReference.replace(LUA_SCRIPT_GLOBAL_KEYWORD + '.', '').toLowerCase();
+
+                if(parsedFiles.has(key)){
+                    this.options.onError?.({
+                        filePath: fullPath,
+                        line: 0,
+                        message: `Duplicate file key detected: ${key}. This can happen if two files have different capitalization. Lua is case sensitive, but the compiler treats file keys as case insensitive.`
+                    });
+                    continue;
+                }
+
                 const parsedFile = new ParsedFile(key, luaFile, fullPath);
 
                 parsedFiles.set(parsedFile.fileKey, parsedFile);
@@ -134,13 +144,7 @@ function fileReferenceToLuaVariable(fileReference: string): string {
     // Convert to ScriptGlobals.folder.FileName format
     let result = LUA_SCRIPT_GLOBAL_KEYWORD;
     for (let i = 0; i < parts.length; i++) {
-        if (i === parts.length - 1) {
+        result += '.' + parts[i].toLowerCase();
-            // Capitalize first letter of filename
-            result += '.' + parts[i].charAt(0).toUpperCase() + parts[i].slice(1);
-        } else {
-            // Folder names stay lowercase
-            result += '.' + parts[i];
-        }
     }
     return result;
 }