Error on 'flush tables' command

[Hank]

I'm getting an occasional error from one of my slaves running
community mysql 5.5.16:

'Got an error writing communication packets' on query.  Query: 'flush tables'

Which halts replication on this slave until I issue a 'SET GLOBAL
sql_slave_skip_counter=1' command on the slave.

There are a few FEDERATED tables on the slave.. is that what would
cause a communication packet error?

If not, what else could cause this on a "flush tables" command?

Thanks.

-Hank