I need help using a workflow to update a custom date/time field in the Deals Module.

Basically, I want to run a report that shows me the last "Appointment Date" for a Deal. To do that, I need a new event to populate the "From" date in the Appointment Date field in the deals module. 

Currently using this and it's not working:

2. eventDetails = zoho.crm.getRecordById("Events",eventId.toLong());
3. seid = ifnull(eventDetails.get("RELATEDTOID"),"");
4. semodule = ifnull(eventDetails.get("SEMODULE"),"");
5. fromdate = ifnull(eventDetails.get("Start DateTime"),"").toDate();
6. if(semodule == "Deals")
7. {
8. mp = Map();
9. mp.put("Appointment_Date",fromdate);
10. updateResp = zoho.crm.updateRecord("Deals",seid,mp);
11. info mp;
12. info updateResp;
13. }