Thaks for your reply.
I want to tell you thath I have the Openemr 5.0 hosted. I have followed the link you sent to install and configure the form.
The main point is that the plot is not showed al all after saving the data. The data is already saved with no trouble, but when you select the item to plot and click on the Plot Selected Items it does not appear the plot.
Due to my Openemer is hosted I can not access /var directory but I wanted just to clarify what exactly the problem is.
Thank you in advance for your help