Could there be a sporadic connection problem? That's what the error message seems to suggest.

Also, try checking the logs of the agent jobs on the publisher, distributor and subscriber. And look at the MSrepl_errors and MSrepl_commands tables and the sp_browsereplcmds procedure in the distribution database to track down more information.

Sorry not to be more help, but replication issues can be extremely tricky to track down. I've had different issues myself but found the above tables and logs to be much more useful than replication monitor in getting to the root of the problem.

Duncan