EXC_BAD_ACCESS Error - Excel 2011

Hi - I have a fairly new Mac Book Pro and in the last few days I have started having a problem with Excel. Not all the time, only with a few files that were sent for work that other people can open with their Macs but I can't. I have previously been able to open earlier savings of the file but not the latest (there are no changes to the senders Excel version etc). I am still able to open other files but not the latest ones.

I have tried rebooting my computer and searching Google etc but can't figure out what the problem is or what to do (btw I know NOTHING about computers!)

Any help would be greatly appreciated!!

The following error comes up:

Microsoft Error Reporting log version:2.0

Error Signature:

Exception: EXC_BAD_ACCESS

Date/Time: 2014-02-07 20:28:21 +0000

Application Name: Microsoft Excel

Application Bundle ID: com.microsoft.Excel

Application Signature: XCEL

Application Version: 14.0.0.100825

Crashed Module Name: unknown

Crashed Module Version: unknown

Crashed Module Offset: unknown

Blame Module Name: unknown

Blame Module Version: unknown

Blame Module Offset: unknown

Application LCID: 1033

Extra app info: Reg=en Loc=0x0409

Crashed thread: 0