graphing problem

I'm a graphing newbie and can't get the graph to work. Could anyone please help? This is to measure internet latency, the test is called "internet". This is running over four hosts, so we should be getting four sets of graphs. The rrd file is created, but I just see NaN values, no data is being recorded. 
 
many thanks, Phil
 
I've got the following data coming in from an ext script every 10 mintues:
 
google : 0.15
businessspectator : 1.28
bloomberg : 0.05
 
I set this up as a gauge graph. Here is one of the entries:
 
	    <ds>
			    <name> google </name>
			    <type> GAUGE </type>
			    <minimal_heartbeat> 600 </minimal_heartbeat>
			    <min> NaN </min>
			    <max> NaN </max>
 
			    <!-- PDP Status -->
			    <last_ds> U </last_ds>
			    <value> 0.0000000000e+00 </value>
			    <unknown_sec> 172 </unknown_sec>
	    </ds>
 
Here are the config files.
 
 
in xymonserver.cfg:
 
I added this to the GRAPHS string: internet=ncv
 
and put in this line after that 
 
NCV_internet="google:GAUGE,businessspectator:GAUGE,bloomberg:GAUGE"
 
 
graphs.cfg:
 
[internet]
	    TITLE Internet Latency
	    YAXIS Seconds
	    DEF:google=internet.rrd:google:GAUGE
	    DEF:businessspectator=internet.rrd:businessspectator:GAUGE
	    DEF:bloomberg=internet.rrd:bloomberg:GAUGE
	    LINE2:google#00CCCC:Inode cache
	    LINE2:businessspectator#FF0000:Dentry cache
	    LINE2:bloomberg#00FF00:In 
	    COMMENT:Time to load home page in seconds.\n