Instead of:
=IF([Game Stats-1.xls]Game-1'!$I$6="MY TEAM
ROSTER",IF(ISERROR(VLOOKUP($A$2,[Game
Stats-1.xls]Game-1'!$J$8:$J$25,1,FALSE)),"",(VLOOKUP($A$2,[Game
Stats-1.xls]Game-1'!$J$8:$J$25,1,FALSE))/$A$2))

With Game Stats-1.xls simultaneously open,

Try this simpler alternative in the destination sheet:
=IF('[Game Stats-1.xls]Game-1'!$I$6="MY TEAM
ROSTER",IF(ISNA(MATCH($A$2,'[Game Stats-1.xls]Game-1'!$J$8:$J$25,0)),"",1),"")

Believe it achieves your underlying intents
--
Max
Singapore
http://savefile.com/projects/236895
xdemechanik
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