You mean other than the duplicate insert ?
If so there are a few cases (top of my head :-) )
1. Adding user to primary database without adding login on replicate server first
2. Transaction Log on replicate is full (if it is a shared database)
3. Locks run out ...
4. Replicate database is full
5. Any other error where a normal valid DML would fail run time
HTH
Avinash