Frequent Errors when editing event or other Structure Items

When I try to edit code either in the Normal View, Structure View or even in popup edit boxes for events, I have all sorts of problems. I frequently get the message "Sandbox not created" on my first attempt to save a change. In the normal view any attempt to change anything (even add a space) gets me the message "Class Not Defined on line 1". Also many time after I make a change and it appears to be saved the change seems to disappear. Sometime what shows in a popup edit box for an event doesn't seem to make it into the normal or structure views... and frequently when I save the entire project nothing is written. I am running with a down level version of Sigma Visual ? How can I check ?