Function arguments prompt causing problems

I've coded several functions that access my company's back-end database. Each function calls a procedure to check if the ADODB.Connection exists and is active. If it isn't, a custom login prompt form is displayed. All this works very well.

My problem is that if the user hasn't logged in yet and prompts one of these functions, the login form is displayed, but the UserForm_Activate procedure didn't run, and when I click the "Log in" button, no code is executed. All I can do is close the form.

Any ideas? If there's a way to prevent Excel's "Function arguments" prompt screen from trying to run my function, that's acceptable, but I'd much prefer if the login form would work in this scenario.

--Bryan