Hi there
When you copy a macro button (or a sheet with a button) to a different workbook then the macro assigned to it is the macro in the original file. So when you click the button it will open the original file to find the original macro code.
You can see this by right click on the button, left click Assign Macro and note that the macro name in the title box refers to another file.
What you need to do is copy the module from the original file into your new file. Have both files open, then in the VB Editor find both projects in the Project window and simply drag the module from the original file to the new file (this produces a copy). Now you need to reassign the macro in your new file. Right click the button, left click Assign Macro, set the lower dropdown box to "This WorkbooK". The macro names in the main window will now drop any filename prefix and just leave the macro name. Select the one you want.
EDIT: The above is based on a button from the Forms toolbar. I rarely see a need to use a command button, but presumably the same applies.
Regards
Derek