Some of the suggestions on this page are not grammatically valid. In fact, the phrase you propose is not grammatical. Since you don't provide context, I'll do my best to narrow things down for you.
There won't be anything happening to her
Is possible (i.e. is grammatical), though unlikely. This would probably be a sentence uttered by someone assuring another person of the safety of a female in the sense of
Don't worry. There won't be anything happening to her (Nothing will happen/is happening to her)
It could also be:
There won't be anything that happens to... (e.g. interfere with the process)
Using "happens to" in the sense of "to chance", giving us
There won't be anything that might interfere with the process.
Unless you provide more context (i.e. the article where you found it) I won't be able to help further. I can just confirm the phrase is not grammatical.