Direct and indirect object

Hi,
He gave some roses to her.
I sent the deposit to them.

Are the sentences correct or it should be:

He gave her some roses.
I sent them the deposit.

These sentences are all fine.

I ask because I have read that pronouns shouldnt be at the end of the sentence

In my book there is a note to avoid using pronouns as a direct object. There is an example:

OK: Peter gave them to Sally.
NOT: Peter gave Sally them.

It's true that there are some combinations that don't work.

There are all okay:
I gave the cookie to Peter.
I gave Peter the cookie.
I gave it to Peter.
I gave it to him.
I gave the cookie to him.

These two are not:
I gave him it. (You may hear this, but not in someone thinking carefully before speaking and not in writing).
I gave Peter it.

Barbara and Clive, thanks for your clarification.