run-time error '9': Subscript out of range - WHY??

[Guest]

I use the following code to control program flow on startup. It works fine on
2 other PCs (and worked on my PC last week), but (now) I get "run-time error
'9': Subscript out of range" when it runs on my PC.

Any ideas what might be different between the two PCs that causes it to
bomb? I have tried rebooting and compared vba references between the two PCs
-can't see anything obvious. Would appreciate any suggestions.
*****

Sub Workbook_Open()
If WorkbookExists("UPE_Period.xls") Then
BuildALL
Else
Sheets("Reports").Select
End If
End Sub
******
Public Function WorkbookExists(WorkbookName As String) As Boolean
On Error Resume Next
If Application.Workbooks(WorkbookName) Is Nothing Then
WorkbookExists = False
Else
WorkbookExists = True
End If
End Function

 

[JE McGimpsey]

Looks to me like there's no sheet named "Reports" in the active workbook.

 

[Guest]

Sorry - should have been more explicit in my original post -
1) there is a sheet named "Reports" in the active workbook
2) it is failing on the call to the WorkbookExists function
3) I run the same exact worksheet on two different PCs - it fails on one but
NOT the other

Thanks for the input though.

 

[Guest]

Just in case someone looks at this later ... I found my problem ...
Under Tools / Options - General Tab (in the VBA programming window)

Error Trapping - Break on All Errors was selected
changed to
Break on Unhandled Errors (to match the working PC)
now works the same on both!