If you are unable to open your archive file from outlook, looks like it got corrupted; there is a tool that might help you fix the file.
Open up explorer and then browse down to the following folder for Outlook 2007, and run the file SCANPST.EXE:
C:\Program Files\Microsoft Office\Office12\
Once you open up the utility, you’ll have to find the location of your PST file by clicking the Browse button.
Click on the Start button to start the scan…
It will take a while to scan the file, and you’ll get a report at the end telling you whether you have errors in the file. See the image below:
Click on the Repair button, and after a while you’ll finally get the “Repair complete” message.
A log file was created, open it in order to know what was fixed on the file.
At this moment you can try to remap the file in outlook.
Source: http://www.howtogeek.com/howto/microsoft-office/fix-your-broken-outlook-personal-folders-pst-file/