run time error 424 in IB TWS Excel DDE API; failed to add combo orders

External question — Quantitative Finance Stack Exchange Author: null Original post: https://quant.stackexchange.com/questions/15076 License: CC BY-SA 3.0 — https://creativecommons.org/licenses/by-sa/3.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I'm using an Excel DDE to connect to Interactive Brokers TWS via their API 9.72 sample, excel 2013. When I tried to create a combo order, the rum error code 424 said "object required". It seems that something is wrong with the "ComboLegForm" Userform. The code is too long to paste here, and I don't find anywhere I can attach the file. The xls file is located in TWSAPI/samples/Excel/TwsDde.xls Thank you for helping.