Use Combo Box Values To Define File Path

I created a series of combo boxes to accept values from the user. These values are intended to be used to build the name of a file they want to see. I tried to set whatever gets selected in each of the combo boxes equal to a distinct variable and inserted each variable into the file path at the appropriate point. I then created a variable for the file path and inserted the file path variable into code that opens that file, copies a particular worksheet, and pastes it into a new sheet in the “master” (the one with the form) workbook and labels it according to what it was named before.

The problem I’m having is that Excel says it doesn’t recognize the file path I’ve given it. Judging from the file path it quotes in the message, it’s not seeing my variables (only the part of the file path I entered in quotes) and then, later when I “debug” it says the variables are not defined. I’m wondering if there is more to defining a variable than what I’ve done. On the form page of code, I declared the following variables: The UserForm Code

Option Explicit
Public strPerformBySubtask As String
Public strPerformBySubelement As String
Public strPeriod As String
Public strMonth As String

I populated each combo box ok and remembered to call the sub procedures below, show the form, hide the form, et al. I think the problem might be in the sub procedures below that I thought would define the variables by setting the respective combo box output equal to a distinct variable I could use in the file path:...........................