As the name of the script says, attach flash could not work with an animated gif, which is what your lightning seems to be.

Try a moon or such prop to give you the curvature of the sky and attach flash script.

Then with the help of Viegoth's wonderful tool you can attach this gif to the script.

An example:
http://hosted1.zyberwerx.net/uthertech/gif2swf.swf?src=your gif url

Alternately you might try to convert your animated gif to a swf file with this tool:

Free Gif to SWF Converter

Upload the file to smugmug, directupload or another picture hosting site which accepts SWF file formats. There you will be issued a hotlink for this file which you then use for the attach flash script in world.

The script gives you the options to adjust the background via transparency, the colors as well as a fade option via alpha setting. You can customize your lightning to fit you existing sky.



Have fun!

CCD_Rum


credit where it's due