How to triggers rules 90 days before Closing Date?

I got error when I tried to create a Rule Trigger, to be executed 90 days before Closing Dates of Potentials.

The error is " The Date of Execution should be LESS THAN 20 days from Closing Date".

I am trying to show a "List of Potentials expiring in 90 days" on Home module.
Second best solution would be automatically created Tasks 90 days before Closing Dates of Potentials.

How can we do that?

This is a single critical requirement that affecting our decision to buy Zoho CRM service.

Thank you,

Singgih