msi: dest_path refers to the directory prefix, not the entire file path.

dlls/msi/files.c

@@ -901,13 +901,11 @@ static UINT ITERATE_DuplicateFiles(MSIRECORD *row, LPVOID param)
     }
 
     dest = build_directory_name(2, dest_path, dest_name);
-    create_full_pathW(dest);
+    create_full_pathW(dest_path);
 
     TRACE("Duplicating file %s to %s\n",debugstr_w(file->TargetPath),
                     debugstr_w(dest)); 
 
-    CreateDirectoryW(dest_path, NULL);
-
     if (strcmpW(file->TargetPath,dest))
         rc = !CopyFileW(file->TargetPath,dest,TRUE);
     else