Please post your code within code tags as requested (use # button on posting toolbar) and properly indent to make it easier to troubleshoot. I don't have your sheet or pivot table so I've commented those out to illustrate things like how to post code, indent, use With blocks correctly, etc. You cannot save a regular file as a binary file (xlsb) just by changing the extension in the name. Correct method shown.
Code:
Function xls_update(myfile, myfilenew)
'** myfile is the origin file - myfilenew is the new i will saveas **
Dim xl As Object
Set xl = CreateObject("Excel.Application")
With xl.Workbooks.Open(myfile, , True)
''With xl.Sheets("Statistics")
With xl.Sheets("Sheet1")
''xl.Sheets("Statistics").Range("B1").Select
.Range("B1").Select
''.PivotTables("PivotTable1").PivotFields("ASSET").Orientation = xlHidden
''xl.Sheets("Statistics").Range("B2").Select
.Range("B2").Select
''.PivotTables("PivotTable1").PivotFields("CLUSTER").Orientation = xlHidden
End With
xl.DisplayAlerts = False
myfilenew = Mid(myfile, 1, Len(myfile) - 5) & "-R1.xlsb"
.SaveAs Filename:=myfilenew, FileFormat:=50
.Close
xl.DisplayAlerts = True
End With
'Kill (myfile)
Set xl = Nothing
End Function
If you still get that error, check your sheet name spelling - note that sheet names are case sensitive.