Since Lighting Effects files are only about 1k, I'm sure it'd be no problem for someone to email it to you, but we'd need to know a few things, first:
A) which version of
PS are you using
B) which file is missing (look in \Program Files\Adobe\Adobe Photoshop XX\Plug-ins\Filters\Lighting Styles and make a list of what's there so we can see what you need)
C) where to send it.
I have CS2. If that's what you're using and don't want to put your email in this forum, send me a PM.