Im having family problems, someone told me to do a ritual by using yellow rose petals and whtie and put them through my house and pay and that will give me prosperity in my house! I just want to know if that is bad if its against my religion?? I'm so confused :/

It is always good to pray ( I assume you mean pray, not pay)
The yellow rose petals and white flowers have nothing to do with it.

If you are praying to God, it is great, if you are praying to some other spriit for the flowers and some spell, it is against your faith.

What branch of the Roman Catholic church do you belong to that would teach that? Not sure who you heard that from, but you did not hear something that is supported by any church teaching or doctrine. Sounds like something cultural or based on a story.

I agree with Fr. Chuck that while spreading flower petals does no particular harm, it is who you are praying to and why and how you are praying. If you are praying for protection against some force, best thing would be to seek the counsel of your parish priest.

There are a lot of silly traditions and myths out there, if you want to sell your home you bury this statue of a saint in the yard, a lot of stores sell these in home selling kits, and of course a lot of these myths come from some of the traditions of other spells and the such which were combined into a christian tradition. ** not officially accepted but done esp in some ethnic groups.

Perrsonally I have asthma, keep flowers out of my home please.
And some stores sell "prosperity" candles, and other "scared" candles that are suppose to do this or that. It takes the idea of catholics in burning a candle for a prayer request, but then takes advantage of this belief by selling a "special candle" that is high priced for it.

I don't think the question you need to be asking yourself is 'should I do this or is it against catholic teaching?'- what you really need to examine is WHY do catholics believe it is/is not right to perform this type of ritual... WHY does the person you received this advice from believe it is right/beneficial to perform this type of ritual? Research, read, learn, expand your understanding beyond what you've been taught to believe, and search for what you actually believe- that's the hard part- because then you need to make an intelligent decision based on the information you've obtained and what you feel is right for you.
The only absolute truths that exist are those in your own heart. And no person or religion can give your objective direction on that. It has to come from you.
So read up on Catholic teaching, find out where that ritual originates and why they believe it produces the results it does... weigh out your options, what YOU believe and think, and then make your decision.