It's not just the script that could cause the problem. It's most probably the frames. When Feditor gives the message: "Unexpected error loading or reading the script" it's one of the following problems:
The palette of one or more frames is over 16. The 16 colours you're allowed to have include the background colour, as well as the black outline. The proportions of one or more frames are incorrect. The must be 248x160, or if it's a pierce frame: 488x160 The palette of one or more frames do not match with the standing frame. Use Usenti to check of they match. The frame stated in your script does not exist. This is the result of a typo eg. typing Attck1.png instead of Attack1.png.
To see which frame in specific may be source of one of these problems, check the "Last path" that Feditor gives below the "Load Script" button.
Blue Druid's post in Help with Animation insertion was marked as the answer