Open Event Error

Greets.

I am relatively new to the world of programming for Excel, and am working to learn the basics. I have been going off of a Excel 2003 programming tutorial, from which I have learned a fair amount. Unfortunately, there is one issue I have been unable to find a solution to.

I am trying to get a module to execute as soon as I open this particular excel document. The following code has been written into the "ThisWorkbook" Open Event window as told to do so in the tutorial:

Private Sub Workbook_Open()
    TimeSheets
End Sub

The modules I have built are as follows:
Module1
MyFirstMacro
TimeSheets

Every time I open the excel file, instead of executing TimeSheets, I get an error: "Compile Error: Expected variable or procedure, not module."

I have been unable to figure out exactly why this is happening. Any thoughts to help me get through, what I assume is an incredibly basic, hurdle? I would be much obliged!