Formulas work in online Google Docs version but not in offline version

Sorry it's not a VLOOKUP issue as I originally thought but array formula issue.

This is the actual culprit:
=IFERROR(INDEX($E$7:$E$99999, MATCH(0,COUNTIF($O$6:O6, $E$7:$E$99999), 0)),"")
If I go to the cell containing this formula and hit Ctrl+Shift+Enter, it does work offline, too. However I have to do the same in multiple instances and it's not practical. Is there a way to "force" Excel sheet treating these as array formulas when downloading from Google Docs?

The online version of this formula goes
=ArrayFormula(IFERROR(INDEX($E$7:$E$99999, MATCH(0,COUNTIF($O$6:O6, $E$7:$E$99999), 0)),""))
How can I change it so that it also works offline in Excel 2010?

Panic over, I fixed it by editing the formula as goes:
Original formula on Google Docs:
=ArrayFormula(IFERROR(INDEX($E$7:$E$99999, MATCH(0,COUNTIF($O$6:O6, $E$7:$E$99999), 0)),""))
Edited formula, works both in Google Docs as well as in offline Excel 2010
={(IFERROR(INDEX($E$7:$E$99999, MATCH(0,COUNTIF($O$6:O6, $E$7:$E$99999), 0)),""))}