Forecast end date always after the calendar end date

 Hi,i'm developing a custom forecast solution and I find an error when I try to run the forecast function in a rule group. The exception returned is:

ERROR: Cannot processMenuEvent 334 - WorkbookException: ForecastException: The Forecast Start Date plus the Forecast Length has run past the end of the Calendar.

The Forecast Start Date is on november 2013, and the calendar ends in july 2014; even putting the forecast length at 1 in the rule returns the same error. The forecast start date is a Date measure, while the forecast length is an int measure.

The forecast is made at the week calendar level.