A trigger returned a resultset and/or was running with SET NOCOUNT OFF while another outstanding result set was active

I have 2 servers connected over a low speed wan and we're running SQL Server 2008 with Merge replication.

At the subscriber, sometimes when attempting to insert new rows, I get this error:

A trigger returned a resultset and/or was running with SET NOCOUNT OFF while another outstanding result set was active.

• My database doesn't have any triggers; the only triggers are the one created by the Merge replication
• Also, whenever this error occurs it automatically rolls back the existing transaction
• I am using DataTables and TableAdapters to insert and update the database using transactions

What I have checked:

1. the database log file size is below 50Mb
2. Checked the source code for Zombie transactions (since I wasn't able to retrieve the actual error at the beginning)
3. Checked the connection between the two servers and found it congested

Questions:

1. How to avoid this behavior and why it's occurring at first place?
2. Why it's cancelling the open transaction?