I'm getting a type mismatch error on the following section of code - any ideas?

========
Set wsDest = Workbooks("NI Insurer Market Share as at " & Format(Date,
"yyyy-mmmm") & ".xls").Worksheets(Array("PC (Chart)-NI-MONTH", _
"PC (Chart)-NI-YTD", "PC (Chart)-NI-R12", "HH (Chart)-NI-MONTH", _
"HH (Chart)-NI-YTD", "HH (Chart)-NI-R12", "CV (Chart)-NI-MONTH", _
"CV (Chart)-NI-YTD", "CV (Chart)-NI-R12"))
========

Thanks in advance