I think you might be getting confused because of the naming of your line items and are mistakeningly adding the same line item (Entries Cumulate) to itself. Take a look at the below and see if this is what you are wanting.
Thanks for your response. As background, I am trying to replicate an excel model in Anaplan. The error message I received was when I attempted to add the following formula to the Closing line item: Closing = Opening + Entries (Cumulate). Entries (Cumulate) being the cumulative of 'Entries' which in turn depends on the the Opening balance in that period. Normally the closing line item formula would simply reference the entries in the period and everything would be fine. However, the current Excel model (which i have 'inherited') references the cumulative position to work out certain line items (I have just shown an illustration in my example) in the actual model there are many line items.
Thanks so much for your help. Based on your suggestion, I have amended my formulas to use PREVIOUS rather than CUMULATIVE. As noted previously, using CUMULATIVE produced a circular reference error. However, using PREVIOUS instead works perfectly (presumably because this formula specifies the precise cells). I thought I had tried this before but obviously not! Your suggestion prompted me to try again (see screenshots below). Thanks again!