Please Help???

[Access_help_rob]

Hey there, i have recently put together a report with a graph in which shows the cumulative increase of some data. Now i know my underying querie contains all the correct data, and every day a new date is added with that days data which is all correct. However my problem is that when i run my report sometimes the graph will show the correct data which is fine, but then i can come out of the report and go back in and the data will be right for some but not for others, as you can see if i get the wrong data in the graph this is going to cause big problems.
Upto now alls i have done is gone to the graph properties and my link master and child field are stock code, so i then added stock code to the box above "row Source" please help thanks
rob