Excel VBA Error Code 424 Object Required

Hi

I keep getting an error message on the macro I have built but I am not sure why. I keep getting the error "Object Required".

I have built a macro whcih uses the list in the current workbook to open two documents and then loop through the list and find the cell content in A:A of the first document opened and paste it into the second document open. The macro opens the two documents however when it comes to activating the first workbook (which contains the macro and list) it brings up this error.

Set IAPLUS = Workbooks.Open("P:\Source code and files\IA+ New Members.xls")

IAPLUS.Activate

Set IAPLUSSht = IAPLUS.Sheets("Sheet1")

Set Template = Workbooks.Open("O:\IA Plus\IA+ members - TEMPLATE.xlsx")

Set Workbook = Windows("IA+CHECK.xlsm").Activate

I have highted the line it debugs on and produces the error.

Can anyone explain why it produces this error?

Thanks,

Jeskit