Problems with a table in a publication

I have a database with two publications, one for SQL CE Clients with filters that send each client its data and keeps it database with "low weight" filtering data not older than a week, and the other publications for SQL Servers.
The publication for SQL CE Clients works excelent, the other one has this problem:

In the publisher i can insert data that should be replicated to subscribers, but subscribers don't receive it. And if I try to insert both in the publisher and the subscriber, the subscriber throws a Primari Key exception.
In the other way, if i insert the data in the subscriber, when it synchronizes, the publisher pulls this data to the table and keeps it, but deletes the subscriber table due to a "conflict". And it never sends the data back to the subscriber, keeping the subscriber's table always clear.

Any Idea?

Thank you.

Omar.Rojaswhat kind of replication are you using is it merge, transaction or snapshot