when i try to install a new theme it says that litestep needs certain modules for the theme to function properly and they have to be downloaded, but when i try to download they dont download and i have to revert back to the original theme.....why?

if these themes are among the latest, they maybe make use of the latest module versions, some of which are not on the default download sites (if you used omar's installer).
check the netloadmodule docs and put ls-universe.info into your step.rc as a module source.

Well I have the issue. I did what Elf said & it downloaded all the modules except 2. Is there anyway to get like a module pack so we don't have this issue anytime we try to install a theme?

Manually download the modules from either here, loose-screws.com, or shellfront.org .

Open step.rc in your Litestep directory. There should be one or more *NetLoadModuleSite lines in there. Those are the sites that NLM attempts to download modules from. I use the following:

If your step.rc doesn't include these sites yet try to copy&paste them from above and try the whole theme installing/modules downloading cycle again.