Had a problem crop up at a customers site with Outlook 2010 erroring with “Microsoft Outlook can’t start Microsoft InfoPath” every time Outlook was started, If you clicked Yes to repair, It didn’t, if you clicked No then Outlook performed as it should.

Checked all add-ons, but there weren’t any that referenced InfoPath, started in safe mode & had the same error, after lots of Googling found a reference to an earlier version of Outlook, thought I had nothing to loose so tried the suggested fix but locations were slightly different and it worked.
If you have this problem with Outlook  2010 on Windows 7 then give this a try..

Run Regedit & go to HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Options\Mail

Create a new DWORD called “DisableInfopathForms” & set the value to 1

Start Outlook & everything should be ok now.

As Dean noted below, if you have the same issue with Office 2013 then try this

Run Regedit & go to HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Options\Mail

Create a new DWORD called “DisableInfopathForms” & set the value to 1

Start Outlook..