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For more information about common Linux technologies and applications, see the following. This error is reported by the small sun in the pnp command on the monitoring server.
OK: Initalising
OK: Using/usr/local/nagios/share/perfdata //
OK: RRDTool/usr/local/rrdtool/bin/rrdtool found.
! : RRDTool/usr/local/rrdtool/bin/rrdtool not executable

When I run rrdtool again

-Bash: rrdtool: command not found
But I will execute./rrdtool again in/usr/local/rrdtool/bin /.
RRDtool 1.3.8 Copyright 1997-2009 by Tobias Oetiker
Compiled Sep 3 2009 15:56:15
Usage: rrdtool [options] command command_options
Valid commands: create, update, updatev, graph, graphv, dump, restore,
Last, lastupdate, first, info, fetch, tune,
Resize, xport
RRDtool is distributed under the Terms of the GNU General
Public License Version 2. (www.gnu.org/copyleft/gpl.html)
For more information read the RRD manpages

Now let's look at the pnp log File tail-f/usr/local/nagios/var/perfdata. log.
01:25:18 [25906] **** TIMEOUT: Timeout after 5 Sec .****
01:40:11 [27266] **** TIMEOUT: Timeout after 5 Sec .****
01:30:12 [5912] **** TIMEOUT: Timeout after 5 Sec .****
19:40:12 [15362] **** TIMEOUT: Timeout after 5 Sec .****
02:30:13 [20785] **** TIMEOUT: Timeout after 5 Sec .****
17:30:11 [8384] **** TIMEOUT: Timeout after 5 Sec .****
02:00:10 [5642] **** TIMEOUT: Timeout after 5 Sec .****
11:35:12 [7187] **** TIMEOUT: Timeout after 5 Sec .****
01:20:17 [17894] **** TIMEOUT: Timeout after 5 Sec .****
04:30:14 [11078] **** TIMEOUT: Timeout after 5 Sec .****

I don't know why the connection times out. Why is the problem?