VSP appears to be having some problems plotting out charts. Apart from being very slow (which has been the case for quite a while), I get an error message when trying to plot B and C scale charts which states "Oops! Looks like something went wrong on this page. AAVSO staff has been notified of the problem". The problem is more acute in the more crowded fields. Has anyone else being experiencing this?
In my experience the problem is intermittent. A while ago I was plotting a number of charts with field widths of 180 and 300 arc min, to see charts for images taken through a camera lens. Limiting mag was I think 13 or 13.5. The long delay issue appears frequently. The failure to plot with the error message you quoted appeared intermittently. I can't remember if the failure to plot correlated with crowded fields.