[Xymon] Xymon Graph propagated with -nan

Hello,

I have a custom monitor that I created which will monitor connections and requests. (http://pastebin.com/bdLZfFAW) The monitor works properly, however the graphing does not. This image displays what is wrong with the graph: http://imgur.com/ZFKkPYs. I have also attached my rrd dump of this monitor. (http://pastebin.com/CRadmAHu) Finally, attached is the graph definition for the test, located in graphs.cfg (http://pastebin.com/zX1HNi3p). I know the issue here is that the last_ds is picking up the values as "U", which is bad, but I don't know what to do about it.

Any help would be appreciated, thanks,

Foster Patch Web Server Technician AccuWeather