Guys, thank you for the time spent, let me summarize the situation:
Unfortunately, @marget's solution produces exactly the same error although it was the shortest one.
It was yesterday at 2 AM when I got this error and had in mind to try with a function this morning.
So, I tried:
Sub getParam()
Return txt123.Text
End Sub
' this is just called in CallSubDelayed2's argument.
The result is exactly the same error.
@mc73 - it is only your suggestion from the above three, that works.
I suppose Erel may throw some light on why is this happening. For now, we may use variables ensuring proper program execution.
Thank you both once more!