Intermittent connection issues with check_net and/or NSClien


I’m hoping that someone has run into this before. I’m having intermittent issues with check_nt that produce the error messages:
Could not fetch information from server
Connection reset by peer
No data was received from host

This only happens with 2 remote server, both are Windows 2k3 SQL 2k5 servers. The error message last for about 13-15 minutes, enough time for the notifications to be sent out, then revert back to OK statuses. I have NSClient installed on all of our Windows servers and only 2 are displaying this behaviour. Here are some samples of the check_net commands I’m using:
$USER1$/check_nt -H $HOSTADDRESS$ -p 1248 -v SERVICESTATE -l $ARG1
$USER1$/check_nt -H $HOSTADDRESS$ -p 1248 -v CPULOAD -l $ARG1$
$USER1$/check_nt -H $HOSTADDRESS$ -p 1248 -v USEDDISKSPACE -l $ARG1$ -w $ARG2$ -c $ARG3$

Something else to note…these Nagios service checks have been in place for quite some time, and it’s just recently started acting up.

Any ideas?