OLMAPI32.DLL is part of Office. If you had more than one version of Office, then you will have had more than one version of this file (search C:\Program Files (x86)). It is possible that the program is trying to use the wrong version. I would suggest that you search for this file and see if you have more than one. If there is one relating to a version other than 2007, then rename both (add .old to the filename). Repair Outlook 2007 again, and reboot the PC.
Go to Windows Default Applications app and set Outlook 2007 as the default e-mail application. See if that fixes it. No guarantees