Cannot seem to get the y axis value

please look at the first graph.

i am trying to get the _y value of my mouse when it is roll over the graph. It will reflect the _y value i set for the graph. I should also get value like 95.5, 73. i have settle the x axis but just can figure out the _y value.

below is the link to my.fla http://s31.yousendit.com/d.aspx?id=39U2ES74WW25Y3GT8GPQVA0OJF

i tried delete the unnecessary stuff but still cannot upload into the server here.

please do PM if you need to send the file back to me as i will PM you my email address … .sorry for the inconvience.