Closing Windows

I’m having trouble closing out of window files…each and every time I hit
the “close window” icon (or close under “file”), a box comes up entitled
“Microsoft Visual Basic”. It contains a yellow triangle with an
exclamation point in it and reads “Compile error. Expected End Sub.” I
hit OK and the screen goes blank. When I close the window again, the
“Microsoft Visual Basic” window appears again with the message “This
command will stop the debugger”. I hit OK and thescreen goes blank and
then I can close the window.
Any ideas on what might be causing this, and how I can correct it?
Thanks.