I'm assuming, though, that you are not a QA engineer/Test Automation engineer on the Microsoft Office development team and so do not actually have a need to test the ability to export an excel workbook into some other format. I understand that you want to manipulate the UI of Excel.... but unless you're actually testing Excel, there MAY be a different way to reach your end goal.
Regardless... what you have in your initial code for the Click on the menu is correct... but the error is not something that is a coding problem with your automation code but something a little lower level in the TestComplete code itself. In that case, you should open a ticket at https://support.smartbear.com/message/?prod=TestComplete.
HOWEVER, as indicated in my opening paragraph... if your end goal is simply to take an Excel file and export it to a different format, you can follow the link I put up earlier about manipulating Excel via COM.
Yes. What tristaanogre said is right, and that's why I asked what you were using Excel for in the first place. If we know what you are trying to do with this worksheet, there are other ways around it. Trying to automate Excel (or any other "outside" software) can be a big waste of your time.
